close

Вход

Забыли?

вход по аккаунту

?

Enantioselective Addition of Aromatic Thiols to a Ketene.

код для вставкиСкачать
Experimental Procedure
(S)-4): A solution of(R.S)-4 (40.0 g, 153.8 mmol) in THF(450 mL) wascooled
at - 100 to - 110 C (Et,O, liquid N,)and treated with 1.92 M nBuLi in hexane
(120.2 mL, 230.8 mmol) (40 min. T 5 - 100 C). The solution was stirred hetween - 105 and - 100 C for 2 h. A solution of (-)-7 (63.7 g, 307.7 mmol) in
T H F (100 mL) was then added over 50 min at - 100 ,C. The reaction mixture
was cooled to between - 102 and - 100 C for 1 h and than allowed to warm
up to - 10 Cover 25 min. The mixture was poured into vigorously stirred 5%
aq NaOH and extracted with Et,O. The organic phase was washed successively
with H,O, 5 % aq HCI. H,O. Saturated NaHCO,, and saturated NaCl solution,
dried over Na,SO,, and concentrated. Distillation ( 1 lO-C!0.02 Torr) afforded
421 (CHCI,,
(S)-4 (34.92 g, 87%. 2 9 7 % hy GC. 99% ce[12]. [XI;"=c = 0.04). The combined acidic aqueous phases were hasified (10% KOH).
extracted (Et20). and distilled 90'Ci2 Torr) to afford recovered (-)-7 (62.4 g.
98%). -(S)-4: 'H NMR (360 MHz. CDCI,, 2 5 . C ) : 6 = 0.96(s. 3 H): 1.05 (s,
3 H ) ; l Zl(m.1 H),1.79(hr.s.3H),I.91(m.l
H).1.98-2.lX(m.2H),2.X6(br.
s. 1 H), 5.64 (hr. s, 1 H). 7.38 (s. 5 H). IR (neat): F = 2970. 1705. 14x0. 1440,
980cm-'. MS (70eV): nz/z(%): 151 (13). 123 (100). 109(12), 107(10). 91 (9).
81 (33).
( R ) - 4 ( ~ 9 7 % p u r e h y G C ; Y 9 % ~ ~ . e [ 1 2 ] ,=
[ 1 ] ~427(CHCI,.c
0
=0.06))was
obtained accordingly when ( + ) - 7 was used.
+
[lb] E M. Arnett. M A. Nichols. A. T. McPhail. J Am. Chrin. Su.1990, //Z,
7059.
[I71 Other conditions tested (aq LiOH. dimethoxyethane (DME), 85 C ; aq.
NaOH. THF, 65 ' C ) were inefficient.
[I81 Similar conditions have been previously applied i n the saponification of
esters and amides: E. J. Corey. S. Kim. S. Yoo, K. C. Nicolaou. L. S.
Melvin. Jr.. D. J. Brunelle. J. R. Falch. E. Tribulski, R . Lett. P. W, Sheldrake. J A m Chem. Soc. 1978. 100.4620: D. A. Evans. T. C. Britton, J. A.
Ellmann, f i w u / w h m Le11. 1987, 28, 6141, W. Oppolzer, J. Bldgg, I. Rodriguez. E.Walther, J. An?. Chem. SOC.1990. ll?. 2767.
I191 K. Schank. A. Frisch. B. Zwanenburg, J. Org. Cheni. 1983, 48. 4580.
[20] C. Fehr, .I.Galindo. H ~ YChim.
.
Acru 1986. 69, 228.
Enantioselective Addition of Aromatic Thiols
to a Ketene
By Charles Fehr,* isubelle StempJ and Josk Galindo
Reiceived: January 26, 1993 [Z 58321E]
German version: Angeir. Chcm. 1993, 10.5 1091
[ I ] a) C. Fehr. Chimiu 1991,45. 253; h) C. Fehr, J. Galindo. J A m Chem. Soc.
1988. 110.6909.
[ 2 ] S. Takeuchi. N . Miyoshi, Y Ohgo. C'hm7. Let). 1992, 551 : S. Takeuchi. N.
Miyoshi, H. HirdPd, H. Hayashida, Y. Ohgo. Bull. C h [ w . Soc. Jpn. 1992,
65. 2001; 0.
Piva. 1:P. Pete. TeeiruheihedronLrit. 1990.3I. 51 57: D. Potin. K.
Williams, J. Rebek, Jr.. Angew. Chem. 1990, 102, 1485: Angeiv. Chrm. Inr.
Ed. EngL 1990,29, 1420.
[3] a ) E. Vedejs. N. Lee. J An7. Cheni. Sw. 1991. 113. 5483. b) F. Henin. J.
Muzart. J.-P. Pete. A.M'Boungou-M'passi. H. Rau. Angeir. Chem 1991,
/03, 460; Angew. Chon. Inr. E d Engl. 1991, 30. 416: K. Matsumoto, H.
Ohta, Terruherlron Lett. 1991. 32. 4729; A. Kumar, R. V. Salunkhe. R. A.
Rane, S. Y Dike. J Chm7. Suc. Chm7. Cunm?un. 1991,485: U. Gerlach. S.
Hiinig, Angew. Chem. 1987, 99. 1313; Angeii. Chem. Inr. Ed. Engl. 1987.
Peschard.
26. 1283, L. Duhamel, P. Duhamel. S. Fouquai. J. Eddine. 0.
J.-C. Plaquevent. A. RaVard, R. Solhard, J.-Y. Valnot. H. Vincens. Tkwuhedrun 1988.44, 5495 and references therein; c) for enzyme or antibody-catalyzed enantioselective C-protonations ofenols (up to 9 6 % w): L L . Reymond. K. D. Janda. R. A. Lerner. J A m . Chmi. Soc. 1992, 114.2257: K.
Matsumoto. S. Tsutsumi. T. Ihori. H. Ohta, ihid. 1990, If?, 9614: review:
H. Waldmann. Nuchr. Chem. Terh. Lab. 1991. 39. 413.
[4] For the resolution of racemic 1. see: D. J. Bennet. G. R. Ramage. J. L.
Simonsen. J Chem. Suc. 1940. 418; and ref [Sh].
[5] a ) T. Matsumoto. S. Usui. BUN.Chum. Soc. Jpn. 1979.52.212;R. Buchecker. R. Egli. H. Regel-Wild, C. Tscharner, C. H. Eugster, G. Uhde, G.
Ohloff. Heli,. Chin?. Acru 1973. 56. 2548: T. Matsumoto. S. Usui, Chrm.
Lett. 1978. 105; Y. Masaki. K. Hashimoto. H. Iwai. K. Kaji, ihid. 1978,
1203; h) T Oritani. K. Yamashita. Agnc Biol. Chcm. 1987. 5 / , 1271; and
ref. [la].
[b] (R)-2 has a precious flowery, fruity damascone-like fragrance. whereas
(S)-2 is characterized by a green. metallic. minty, camphoraceous note,
see: C. Fehr. I. Stempf. J. Galindo, Swiss Patent application 13. October
1992.
[7] C . Fehr, J. Galindo. J. Org. Chem 1988, 53. 1828.
[XI E:Z ratios determined by NO€ experiments o n the corresponding Me&
ketene acetals.
[Y] Complexation of enolate 2(Li) with (-)-7(Li) or (-)-7(MgCI) (metalated
(-)-7) prior to protonation with (-)-7 [I h] did not bring any improvement (36% er and < 5 % P P ) .
[lo] Determined by gas chromatography using permethylated P-cyclodextrin
in OV-1701 as chiral stationary phase; column length: 12 m. For use of
short columns, see. M. Lindstrom, J High Resolrrt. Chromurogr. 1991, 14,
765.
[ I l l Above -80 , the enolates 3(Li)~-6(Li)
obtained are converted via ketene
8(7] to 1-(2.6.6-trimethyl-2-cyclohexenyl)-1-pentanone.
[I21 Determined by conversion of 3 - 6 into (2.6.6-trimethyl-2-cyclohexenyl)
methyl acetate [I) LiAIH,. Et,O. 2 ) AcCI. pyridine. Et,O] and GC measurements using permethylated I(-cyclodextrin in OV-1701 as chiral stationary phase.
[I31 Trapping of 4(Li) with Me,SiCI gives almost exclusively ( Z )ketene thiol
acetate ( Z ; E 2 98: 2 by GC). After distillation. the ZIEratio is 83: I 7 (GC
and NOE experiments).
[14] See C . Fehr, I. Stempf, J. Galindo. Angcit. Chen?. 1993, 105. 1093; A n g ( w
Chtvm Int. Ed. En,ql. 1993, 32, 1044.
[IS] The pK, of the substrate and the nucleofugal properties of X are also
critical. Protonation of the cr-cyclothiogeranate enolate with X=SnBu
showed low enantioselectivity (30% w).
1044
t:.i'
V C H Verl(i~.r~e.sellsc/iufr
mhH, 0-69451 Wemheim, I993
In the preceding communication, we reported the enantioselective protonation of Z thiol ester enolates 1(Li) and
2(Li) with 99% ee, using (+)- o r (-)-N-isopropylephedrine
(( +)-4 or (-)-4) as the chirdl proton source.111A prerequisite for the success of this process is the highly stereoselective
formation of a Z thiol ester enolate at low temperature, since
above -80°C enolates 1(Li) and 2(Li) eliminate lithium
thiolate to give ketene 5.
Both preparative and mechanistic considerations directed
our interest to a hitherto unknown reaction, the enantioselective addition of a thiolate to a ketene (e.g. 5 -1(Li)
- + ( - ) - I or (+)-1) in the presence of a chiral proton
donor.[', 31 We now describe the successful realization of this
procedure (up to 97% re) and its extension to a catalytic
version (up to 9 0 % ee with 2-5 mol% chiral catalyst).
ULi) - 3(Li)
5
Ar = Ph
1
2-naphthyl 2
p-C1-C,H4 3
Scheme 1. Enantioselective addition of thiols to 5. The deprotonation of
racemic I and 2 is described in ref. [I j.
Slow addition (3-4 h) of (-)-4 to a solution of 5 and
lithium thiophenoxide in T H F at - 55 "C afforded thiol ester
(S)-1 in 84% yield and 95 % re (Table 1, entry 1). Thiol ester
( S ) - 3 was obtained analogously in 83 YOyield and 97 % ee
from 5 and lithiump-chlorothiophenoxide (Table 1, entry 2).
Since under these conditions the equilibrium between 5 and
l(Li) (or 3(Li)) lies on the side of 5, the reaction rate is
controlled by the addition of (-)-4. This allows rapid and
irreversible C-protonation of the incipient enolate. In this
[*I
['I
Dr. C. Fehr. Dr. 1. Stempf."' .I.
Galindo
Firmenich SA. Research Laboratories
P.O. Box 239, CH-I211 Geneva 8 (Switzerland)
Telefax. Int. code + (22)7803334
Postdoctoral fellow at Firmenich SA (1990 -1991)
057U-OK33/93~0707-1044
S IO.fXJ+.?S/O
Angew. C h u m I n r . Ed. EngI. 1993. 32, N o . 7
manner. the concentration o f ( -)-4 in the reaction medium
is kept low. thus minimizing the risk of proton exchange with
the t h i ~ l a t e . ' ~ ]
Table 1. Results of the reactions following Scheme 1 (stoichiometric and catalytic).
Entry Ar
I
2
3
4
5
6
Ph
p-CI-C,H,
Ph
Ph
p-CI-C,H,
p-CI-C,H,
( - 1-4
Mol
T [ 'C] Addition Reacee [%] Yield [%I
time [h] tion
[a]
[c]
time [h]
100
100
5
2
5
2
-55
- 55
-27
-27
- 27
-27
O h
3
4
3
1
3
3
3.5
4.5
3.5
1.5
3.5
3.5
95 [b]
97
89
71
90
57
84
85
86
87
81
-
[a] For (S)-l or (SF3 the ce values and absolute configurations were determined by GC of the corresponding (2,6.6-trimethyl-2-cyclohexenyl)methylacetate using permethylated P-cyclodextrin in OV-I 701 as chiral stationary phase.
[b] At -78'. 90% P P (72% yield); at -30': 9 3 % ee (83% yield). [c] After
distillation.
We next tried to devise a catalytic process, in which the
aromatic thiol ArSH serves as both nucleophile and proton
source in the presence of a catalytic amount of (-)-4(Li). We
reasoned that if the rate of introduction of ArSH to a solution of 5 and a catalytic amount of (-)-4(Li) in THF is
maintained low enough to avoid accumulation of ArSH
([ArSH] I [( -)-4(Li)]), and if the added thiol is selectively
deprotonated by (-)-4(Li) and not by the intermediate thiol
ester enolate, a catalytic cycle according to Scheme 2 might
be possible. It was envisaged that the mixed reagent ArSLi/
(-)-4 would add in a possibly reversible step to ketene 5; fast
and irreversible C-protonation of enolate complex 6 would
then liberate (-)-4(Li), which re-enters in the catalytic cycle.
value of (-)-I decreased to 77% (entry 4). we next applied
the catalytic conditions (5 mol% (-)-4(Li)) to the addition
ofp-chlorothiophenol (entry 5) and obtained thiol ester ( S ) 3 with 90% ee. The slow addition of the thiols (3 h) turned
out to be critical for inducing high enantioselectivities. When
p-chlorothiophenol was added in 1 h, the ee value dropped to
53 %. Lowering the amount of (-)-4(Li) to 2 mol YOproved
deleterious (57% ee, entry 6) and would presumably require
even longer addition times.
Strikingly, the same enantioselectivity trends are observed
regardless of whether the esters are generated from 5 o r from
the racemic esters by deprotonation/protonation.['.41 Therefore, the mechanism for the chirality-inducing step is likely
to be the same in both processes. Taking into consideration
the successful catalytic process, in which more than 95 '10 of
the protons are supplied by an achiral aromatic thiol, we
conclude that a tight transition-state-like complex of type 6
immediately precedes an irreversible stereocontrolled C-prot o n a t i ~ n . [ ~ -Inspection
"
of Tdbk 1 and footnote 4 shows a
striking parallel between the ee values and the pKa value of
the nucleophile. More acidic thiols such as p-chlorothiopheno1 may be more completely deprotonated to the thiolate; [*I
in addition, the lower pK, of aromatic thiol esters 1-3 would
allow a slower and more selective protonation.
Experirnen tal Procedure
a) (S1-lunder stoichiometric conditions (1 mol equiv ( - 1-4, Table I , entry 1 ) :
A solution of PhSH (1.47 g, 1.36 mL. 13.33 mmol) in T H F (10 mL) containing
one crystal of 1.10-phenanthroline was treated without cooling(35-40'C) with
1.60 M BuLi (8.35 mL, 13.33 mmol) until the colorless solution turned bright
violet. The solution was decolorized by addition of one drop of (-)-4, diluted
with T H F (40mL). cooled to -55°C. and treated with ketene 5 (2.00.g.
13.33 mmol). Over a period of 3 h. a solution of (-)-4 (2.76 g, 13.33 mmol) in
T H F (5 mL) was added with a syringe pump (Bioblock Scientific) (temperature
-55 C ) .The mixture was stirred for 30 min, poured into vigorously stirred
5 % aq NaOH, and extracted with Et,O. The organic phase was washed successively with H,O, 5 % aq HCI, H,O, saturated HaHCO,. and Saturated NaCI,
dried (Na,SO,), evaporated, and distilled bulb-to-bulb (oven temperature
130"C/0.05Torr) to afford (5')-1 ( 2 . 9 0 ~ .84%: 9 5 % re) [I]. The combined
acidic aqueous phases were basified (10% aq KOH). extracted (Et,O), and
distilled to afford recovered (-)-4 (2.70g, 98%).
b) (S)-1 under catalytic conditions (5 mol% (-)-4. Table 1, entry 3): A solution of (-)-4 (322 mg, 0.67 mmol) in T H F (5 mL) containing one crystal of
1.10-phenanthroline was treated with 1.60 M BuLi (0.42 mL, 0.67 mmol) until
the colorless solution turned bright violet. Upon addition of the first drop of
PhSH (55 mg. 0.05 mL, 0.50 mmol) in T H F (0.2 mL) the color faded. The
solution was diluted with T H F (35 mL). cooled to - 27' C (cryostat a t - 30 C)
and treated with ketene 5 (2.00 g. 13.33 mmol). Over a period of 3 ti, a solution
of PhSH (1.35 g. 1.25 mL, 12.30 mmol (total amount 12.80 mmol: 0.96 mol
equiv)) in T H F ( 5 mL) was added with a syringe pump (Bioblock Scientific)
(temperature -27 C). Stirring was continued for 30 min. Workup as above
afforded (S)-l (2.98 g, 9 0 % based on PhSH (86% based on 5); 89% C P ) .
Received: January 26. 1993 [Z 5833 IE]
German version: Angnl.. Ckem. 1993, 105. 1093
Scheme 2. Catalytic enantioselective addition of aromatic thiols t o 5
Indeed, this concept proved fruitful. Continuous slow addition of PhSH to a mixture containing 1 mol equiv ketene
5 and 5 m o l % (-)-4(Li) at -27 "Cfurnished (-)-1 (86%
yield) with 89% ee (Table 1, entry 3). The temperature of
-27 "C seems to be optimal: a t lower temperature the reaction is too slow, and at 0°C the enantioselectivity drops
markedly ( z50 YOee). This is largely due to the consumption of (-)-4(Li) by competing addition to 5 and the accumulation of PhSH. When 2 mol YO(-)-4(Li) was used, the ee
Angm . Ckem. l n t . Ed. Engl. 1993, 32, No. 7
[I]C. Fehr, 1. Stempf, J. Galindo, A n g w . Ckczm. 1993, 105, 1091 : Angen.
Ckem. In,. Ed. Engl. 1993, 32. 1042.
[21 a) For enantioselective amine-catalyzed additions of alcohols to ketenes.
see: H. Pracejus, Liebigs Ann. Chem. 1960, 634, 9; H. Pracejus. G. Kohl.
ihid. 1969, 722, 1 ; A. Title, H. Pracejus. Chenr. Brr. 1967, 100. 196; b) for
diastereoselective additions of chirdl alcohols to ketenes. see: U . Salz. C .
Riichardt, Tetrahedron Lett. 1982,23.4017; J. Jlhme. C. Riichardt, Angev'.
Ckrrn. 1981. Y3, 919; Angcw. Ckem. In!. Ed. EngI. 1981, 20, 885: R. D.
Larsen. E. G. Corley. P. Davis. P. J. Reider. E. J. J. Grabowsky, J Am.
Chwn. Suc. 1989, If 1. 7650; c) for reviews on ketene additions, see: T. T.
Tidwell. Acc. Chem. Res. 1990. 23, 273; H. Buschmann, H. D. Scharf. N .
Hoffmann. P. Esser, Angeir. Ckmt. 1991,480; Angric. Ckrm. int. E d EngI.
1991. 30, 477.
131 For a thio Michael addition/enantioselective protonation, see: A. Kumar,
R. V. Salunkhe, R . A . Rane. S. Y. Dike, J. Chcm. So< Chem. Cnmmun.
1991, 485.
VCH Verlugsgesell.~(~huft
mbH. 0-69451 Weinkam, 1993
0570-0833/Y3/0707-/045 8 10.00f .25f)
1045
[4] Indeed, when 5 was stirred with an equimolar mixture of lithium thiolate
and (-)-4 in THF at -60-C for 3 h, (S)-1 or (S)-3 were obtained with
diminished enantioselectivities of 81 and 94% ee, respectively. Low enantiofacial discriminations (10-40% ee) resulted from the reactions of 5 with
BnSH or BUSH at -70°C and with PhOH, MeOH, or (-)-4 at 20°C.
[ S ] For an enantioselective protonation with intramolecular proton return,
see: E. Vedejs, N. Lee, J. Am. Chem. Suc. 1991, 113, 5483.
[6] The postulated mechanism is in line with related nucleophilic additions to
ketenes, see refs. (2a. c].
[7] For catalytic enantioselective additions of thiols to cycloalkenones, see: H.
Hiemstra. H. Wynberg, J. Am. Chem. Soc. 1981, 103, 417.
[XI p-Chlorothiophenol: pK, = 6.96, thiophenol: pK, =7.76; see: F. G. Bordwell, H. M. Andersen, .l
Am. Chem. Suc. 1953, 75, 6019. Amine-catalyzed
additions of thiols to maleic anhydride also necessitate prior dissociation of
the thiol. Indeed, the rate of thiol addition has been found to be proportional to the acid strength of the thiol, p-chlorothiophenol reacts faster than
nBuSH (pK, 12.4). see: B. Dmuchovsky, B. D. Vineyard, F. B. Zienty, J.
Am. Chem. Soc. 1964, 86, 2814.
Alternating Ferro- and Antiferromagnetic
Interactions in a Chainlike Cu" Coordination
Polymer **
should be noted that examples of alternating ferromagnetic/
antiferromagnetic exchange in 1D chains are very rare.16]
Our first attempts along this line led us to prepare the
dinuclear precursor 1 and the related C u 2 + complex 2. These
compounds were characterized by elemental analysis, IR
spectroscopy, magnetic measurements, and X-ray structural
anaiysis.['I
The crystal structure of 1 consists of discrete, centrosymmetric di-phydroxocopper(I1) dimers with bpym as terminal
ligand, weakly coordinated water molecules, and unidentate
nitrate anions (bound through an 0 atom), and molecules of
water of crystallization. The coordination geometry around
each Cu" ion is approximately octahedral with tetragonal
distortion. The two bridging hydroxo groups and the two
nitrogen atoms of the bpym ligand form the equatorial
plane, and a water molecule and an oxygen atom of a nitrate
anion occupy the axial positions (Fig. 1). The Cu-N and
By Giovanni De Munno, Miguel Julve,* Francesc Lloret,
Juan Faus, Michel Verdaguer, and Andrea Caneschi
One of the best known magneto-structural correlations in
systems with magnetic exchange interactions concerns the
di-p-hydroxo-copper(I1) complexes [LCU(OH),CUL]~+.[']
Systematic studies of this family of complexes have established that the singlet-triplet energy gap J is directly proportional to the Cu-OH-Cu bridging angle 0, leading to a singlet
ground state for B > 97.5" and to a triplet ground state for
0 < 97.5'. The value of 0 ist strongly influenced by the nature of the terminal ligand L. In this respect we have restricted ourselves to complexes that contain chelating N donor
groups as terminal ligands, and for L = diaminer21antiferromagnetic and for L = 2,2'-bipyridinerZb. 31 ferromagnetic
coupling has been observed.
In a recent work, some of us investigated the complex
formation between [Cu(bpym)]'
(bpym = 2,2'-bipyrimidine) and O H - in aqueous solution.[4*The only hydroxo
species whose formation was observed in solution is the di-phydroxo [C~,(bpym),(OH),]~' complex. This complex was
isolated in the solid state as a perchlorate salt, and displays
a relatively strong intramolecular ferromagnetic coupling
( J = 147 cm-I), as expected from the 0 value (95.0"). Bpym
can also act as a bischelating ligand towards transition metal
ions,['] and its ability to transmit antiferromagnetic coupling
makes this dinuclear complex a suitable precursor of alternatingly bridged one-dimensional (1 D) structures with alternating ferromagnetic (through the hydroxo bridge) and antiferromagnetic (through the bpym bridge) interactions. It
+
[*] Prof. M . Julve, Dr. F. Lloret, Prof. J. Faus
Departament de Quimica Inorganica
Facultat de Quimica de la Universitdt de Valencia
Dr. Moliner 50, E-46100-Burjassot, Valkncia (Spain)
Telefax: Int. code + (6)386-4322-02
[**I
8
VCH Verlagsgeseil,whaji mhH, 0-69451 Weinheim, 1993
Cu-0 (hydroxo bridge) distances in 1 are very close to those
observed in the parent compound [Cu,(bpym),(H,O),(OH),](CIO,), 2 H,0.r41The main difference between these
two compounds is that the axial positions are occupied by
two water molecules in the perchlorate species, whereas they
are filled by a nitrate group and a water molecule in 1. The
four equatorial atoms are coplanar; no atom deviating from
the least-squares plane by more than 0.006(2)
The copper
atom is displaced by 0.122(1) from this plane towards the
O(2) atom of the water molecule. Hydrogen bonds link coordinated and uncoordinated water molecules and nitrate
anions (some of them are represented by broken lines in
Fig. 1). The intramolecular Cu(1). ' . Cu(1a) separation is
2.881(1)
the Cu(1)-O(1)-Cu(1a) bridging angle 0 is
95.7(1)".
The crystal structure of 2 consists of chains of copper(I1)
ions alternatively bridged by bpym and two hydroxo groups,
unidentate nitrate anions (bound through an 0 atom), and
uncoordinated water molecules (Fig. 2). Each copper atom
A
Prof. G . De Munno
Universiti della Calahria, Cosenza (Italy)
Prof. M Verdaguer
Universite Pierre et Marie Curie, Paris (France)
Dr. A. Caneschi
Universita degli Studi di Firenze (Italy)
This work was supported by the Spanish DGICYT (Project PB91-0807CO2-01j and the Italian Minister0 dell'Universitii e della Ricerca Scientifica e Tecnologica.
1046
Fig. 1. Molecular structure of 1 (ellipsoids drawn at the 30% probability level).
Selected distances [A] and angles I"] (standard deviations in parentheses):
Cu(1)-N(1) 2.014(2), Cu(l)-N(2) 2.018(2), Cu(1)-O(1) 1.944(2), Cu(1)-O(1aj
1.943(2), C ~ ( l ) - 0 ( 2 2.310(2),
)
C ~ ( l ) - 0 ( 52.691(2);
)
N(l)-Cu(l)-N(2)80.711).
N( l)-CU(l)-O(l) 96.1(l), N(l)-Cu( 1)-0(2) 97.1(1). N(l)-Cu(l)-O(S) 84.3(1),
N(l)-Cu(l)-O(la) 172.5(1).N(Z)-Cu(l)-O(la) 98.0(1), N(2)-Cu(l)-0(2) 91 .0(1),
N(2)-Cu(l)-0(5) 84.7(1), N(2)-Cu(l)-O(1) 172.7(1). O(1)-Cu(1)-O(1a) 84.311).
0(1)-CU(l)-O(2) 95.9(1). O(l)-Cu(1)-0(5) 88.4(1), 0 ( 2 ) - C ~ ( l ) - 0 ( 5175.3(1),
)
0(2j-Cu(l)-O(la) 90.3(1) I l l ] .
A.
A;
0570-0833/93/0707-1046 5 10.00+ .25j0
Anxeic. Chem. Inr. Ed. Engl. 1993, 32, No. 7
Документ
Категория
Без категории
Просмотров
0
Размер файла
394 Кб
Теги
ketene, additional, thiol, enantioselectivity, aromatic
1/--страниц
Пожаловаться на содержимое документа