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Diastereoselective Hydroxyalkylation of the 1-Position of 2-Pivaloyl 1 2 3 4-tetrahydroisoquinoline via Magnesium Derivatives.

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molecules present in the crystal are slightly disordered, but
likewise without cation or anion contacts. The dimerization found with 2 also occurs with other counterions (BrQ,
SO,FQ) and in other solvents (CH2C12).On rapid methylation of 1 with an excess of FS03CH3, a bis(phosphonium)
salt with even stronger activated C=C double bonding is
formed, Further, in a wide sense, related cases of the reaction of phosphanes with activated C=C bonds have already been reported in the literat~re[~.'~.
Received: November 7, 1983 [Z 616 IE]
German version: Angew. Chem. 96 (1984) 237
[l] a) I. J. Colquhoun, W. McFarlane, J. Chem. Soc. Dalton Trans. 1982,
1915. h) The dioxide (m.p. 204°C) and the disu[fide (m.p. 184°C) are
formed on reaction of 1 with NO and elemental sulfur, respectively. The
diselenide has already been described [la].
[2] H. Schmidhaur, Abstr. Int. Conf: Phosphorus Chem., Nice 5. 9. 1983, No.
15; Phosphorus and Surfur 18 (1983) 167.
[3] H. Schmidhaur, R. Herr, J. Riede, Chem. Ber. 117 (1984), in press,
141 Cf. H. J. Bestmann, R. Zimmermann in Houben-Weyl Mefhoden der Organischen Chemie. 4th edit., Vol. E l, p. 616ff., Thieme, Stuttgart 1982.
[5] 2 : 'H-NMR (CDC13): 6(CH3)=2.1 (d, 3H, 'J(PH)=15.0 Hz),
6(CH2)=5.43 to 6.50 (ABXY, 2H), 6(C6HJ)=6.64 to 7.50 (m, 20H); "PNMR: 6(PPh2)= -6.12 (d), 6(PPh2Me)=11.07 (d, *J(PP)=47.3 Hz).-3:
'H-NMR (CDC13): 6(CH3)-;2.02 (d, 6H, 2J(PH)= 11.0 Hz), 6(CH2)=4.0
to 4.63 (m. 4H, ("PI gives singlet signals), 6(C6HJ)=7.3 to 8.03 (m, 40H);
I3C-NMR: 6(CH2)=25.40 to 28.97 (m), 6(CH3)= 13.43 (dd,
'J(PC)=57.62, 3J(PC)=4.8 Hz), 6(C6H5)=120.8 to 133.65 (m).
[6] H. Schmidhaur, T. Costa, B. Milewski-Mahrla, Chem. Ber. 114 (1981)
1428.
171 Colorless, monoclinic crystals from methanol, a = 1354.9(4), b = 1961.0(5),
c=1160.2(3) pm, fl= 116.7(2)", V=2752x lo6 pm3, space group P2,/c,
MoKn radiation, graphite collimator, w-scan
Z = 2 , pCaI.= 1.38 g
(1.1 to 29.3" min-', 20,,,548", linear absorption coefficient 13.1 cm-I).
From 4319 collected reflections, 3335 remained after Lorentz and polarization corrections (77.2%, I > 1.960(1)). Heavy atoms according to the
Patterson method, all atoms other than H atoms anisotropically refined
with full matrix, H-atoms partly found, partly calculated according to
ideal geometry (279 variables, 331 1 reflections), Rl =6.4, R2=7.3%. The
CH30H molecule is ill-defined and disordered. Further details of the
crystal structure investigations are available on request from the Fachinformationszentrum Energie Physik Mathematik, D-7514 Eggenstein-Leopoldshafen 2 on quoting the depository number CSD 50689, the names of
the authors, and the journal citation.
[XI H. Hoffmann, Chern. Ber. 94 (1961) 1331; S . Trippett, Chem. Comrnun.
1966. 468.
Diastereoselective Hydroxyalkylation of the
1-Position of 2-Pivaloyl-1,2,3,4-tetrahydroisoquinoline via Magnesium Derivatives
not be detected by 'H- or I3C-NMR spectroscopy. Furthermore, refluxing a solution of u-2a in methanol/concentrated hydrochloric acid for 8 h produces the ester u-2b
(b.p. 15O0C/0.O05 torr). The diastereomeric ester 1-2b
(m. p. 76-78°C) is formed by refluxing a solution of u-2a
in trifluoroacetic acid/trifluoroacetic anhydride for 2 h.
Both reactions are totally selective as indicated by 'HNMR spectroscopy and give the esters 2b in ca. 90%
yield[']. Reductive cleavage of the esters u-2b and 1-2b with
LiAlH4 (6 h reflux) in THF furnishes (ca. 65%) the amino
alcohols u-2c (m. p. 73-75°C) and 1-2c (m. p. 102105OC), respectively. In contrast, a ca. 2 : 1-mixture of the
amide u-2a and the ester I-2b is isolated from the reaction
of benzaldehyde with the corresponding lithium derivative
of 1. The configurations u and l''] were assigned from the
NMR spectra of the four u/I-diastereomeric pairs of 2a2d. Notably, in the I-isomers of 2a and 2c with intramolecular hydrogen bonds the NMR signals of H-8 show a dramatic upfield shift (up to 1 ppm)['].
BrMg
H5 c 6 AOR2
1
1-2
u-2
a : R' = C O t B u , R2 = H;
b: R'
c: R ' = R 2 = H; d: R ' = R 2
= H, R 2 = COtBu;
COtBu
The adducts 3a-3d with other aldehydes were also
formed completely selectively (NMR analysis), and even
with acetophenone one diastereomer 3e was produced in
96% ds in 909/0yield (see Table 1). The configurations of
the compounds 3 were assigned by analogy to those of the
benzaldehyde adducts 2.
By Dieter Seebach* and Max A . Syfrig
Amide-type derivatives of 1,2,3,4-tetrahydroisoquinolines can be lithiated, and hence alkylated, in the l-positi~n['-~I.
Whereas an overall enantioselective process could
be developed[31, the products of hydroxyalkylation obtained with aldehydes have been reported to be formed
with little or no diastereo~electivity[~~~~.
We have now disthat addition of magnesium dibromide ether to
solutions of the lithiated 2-pivaloyl-1,2,3,4-tetrahydroisoquinoline in tetrahydrofuran (THF) generates a highly
diastereoselective reagent 1l6I.
Thus, addition of benzaldehyde to the solution of the
magnesium derivative 1I6I at -78°C leads to isolation of
the u-isomer of 2a (m.p. 160°C) in 83% yield. I-2a could
Table 1. Products 3 from the magnesium derivative 1 and aldehydes, and a
ketone. % ds indicates the content of the major diastereomer in the crude
product; >97% ds means that only one diastereomer could he detected by
NMR. The values in parentheses are those obtained with 1, Li instead of
MgBr. All yields are > 70%; we assume that the u-isomer is formed in excess,
except in the case of 3e, which has /-configuration according to the 'H-NMR
signal of H-8.
[*I Prof. Dr. D. Seehach, DipLChem. M. A. Syfrig
Lahoratorium fur Organische Chemie
Eidgenossische Technische Hochschule
ETH-Zentrum, Universitatstrasse 16
CH-8092 Zurich (Switzerland)
Addition of magnesium bromide to solutions of the lithiated formamidine 4121, formed from 1,2,3,4-tetrahydroisoquinoline and tert-butylamine, before addition of benzaldehyde, also changes the u/l-ratio of product 2
248
0 Verlag Chemie GmbH, 0-6940 Weinheim. 1984
3
R'
RZ
% ds
M.p. [ "C]
a
H
b
H
H
H
CH3
CzH5
C ~ H SC H Z
COHsCH=CH
3,4-(methy1enedioxy)phenyl
C~HS
>97(75)
> 97
> 97
>97
96 (70)
129
165
182
I68
131
C
d [a]
e
[a] Adduct of 1 and piperonal.
0570-0833/84/0303-0248 $ 02.50/0
Anyew. Chem. Int. Ed. Engl. 23 (1984) No. 3
(R' =CH=NtBu), R 2 = H) from 1 : l f 2 I to 6 :l['O1. The results described here demonstrate once again the decisive
influence of the metal upon the reactivity and selectivity of
even so-called polar organometallic or "carbanion" derivatives.
Access to both diastereomers of products of type 2 and
3 is not only interesting in itself, but should provide selective routes to isoquinoline alkaloids with a-hydroxylated
side chains in the 1-position["].
Received: November 28, 1983 [Z 637 IEJ
German version: Angew. Chem. 96 (1984) 235
[ I ] Reviews: D. Seebach, D. Enders, Angew. Chem. 87 (1975) 1; Angew.
Chem. Int. Ed. Engl. 14 (1975) 15; D. Seebach, J.-J. Lohmann, M. A. Syfrig, M. Yoshifuji, Tetrahedron (Symposia-in-Print) 39 (1983) 1963.
[2] A. I. Meyers, S. Hellring, W. T. Hoeve, Tetrahedron Lett. 22 (1981) 5115;
A. I. Meyers, W. F. Rieker, L. M. Fuentes, J . Am. Chem. Soc. 105 (1983)
2082.
131 A. I. Meyers, L. M. Fuentes, J. Am. Chem. SOC.105 (1983) 117.
[4] D. Seebach, M. Yoshifuji, Helu. Chim. Acta 64 (1981) 643.
151 M. Syfrig, projected dissertation, ETH Zurich.
[6] The structure of the reagent is unknown; ate-complexes or mixed aggregates between RMgBr 1, RLi, LiBr, and/or MgBr, may be involved.
[7] For recent examples of the N.0-acyl migration see: M. J. Lyapova, I. G.
Pojarlieff, B. J. Kurtev, J. Chem. Res. (M)1981, 4083.
[S] D. Seebach, V. Prelog, Angew. Chem. 94 (1982) 696; Angew. Chem. Inf.
Ed. Engl. 21 (1982) 654.
191 Cf. M. Shamma, V. S. Georgiev, Tetrahedron 32 (1976) 211.
[lo] The chiral formamidine from tetrahydroisoquinoline and 2-phenyl-2(trimethylsiloxy)-l-(trimethylsiloxymethyl)ethylamine [3] is converted
into a 5 : I-mixture of u- and 1-2c through the magnesium derivative.Whereas the lithium derivative of the formamidine of piperidine and
t-butylamine gives a 3 :2-mixture of the 1- and u-benzaldehyde adducts
(A. 1. Meyers, personal communication), a l/u-ratio of 1 :2 is found with
the magnesium derivative.
[I I] Examples: ushinsunine, guatterine, ophiocarpine, bicuculline, corlumine etc.; see G. Grethe: "lsoquinolines", Part I of: The Chemistry of
Heterocyclic Compounds, Vol. 38, Wiley, New York 1981; T. Kametani:
The Chemistry of Isoquinoline Alkaloids, Hirokawa-Elsevier, Tokyo-Amsterdam 1969.
r
1
2a ,R'= R L H
I
Photoreaction of Biacetyl and 1,3-Dioxole
Derivatives:
Modification of the Mechanism of
the Photoreaction of Carbonyl Compounds with
Electron-Rich Olefins"*
By Jochen Mattay*, Joachim Gersdorf, Hans Leismann,
and Steen Steenken
The photoreaction of biacetyl 1 with alkenes usually
yields oxetanes and "ene-type" adducts"]; sometimes enol
[*I Dr. J. Mattay, Dipl.-Chem. J. Gersdorf, Dr. H. Leismann
Institut fur Organische Chemie der Technischen Hochschule
Prof.-Pirlet-Strasse 1, D-5100 Aachen (FRG)
Dr. S. Steenken
Max-Planck-Institut fur Strahlenchemie
D-4330 Miilheim a. d. Ruhr 1 (FRG)
I**] The authors thanks Prof. H.-D. Scharf for stimulating and helpful discussions.
Angew. Chem. Int. Ed. Engl, 23 (1984) No. 3
("reduction") products formally derived from abstraction
of a hydrogen atom from the olefin by the diketone (this
corresponds to the first step of the photoreduction)[']. Generally, exciplexes having some charge transfer (CT) character and diradicals are proposed as
According to Wellerl3], both locally excited states
(A*D-AD*) and the CT-configuration (AeD@) contribute to the exciplex state formed by excitation of electron
donor (D) and acceptor (A) molecules. Stronger electrondonor olefins than those used previously are the substituted 1,3-dioxoles 2, which have recently become easily
accessible[']. Irradiation of 1 and 2 should lead to formation of exciplexes with more CT-character (contact ion
pair according to WeZZer[31)
and also include the possibility
of ionic photodissociation in polar solvents[']. We report
here an investigation of the substrate and solvent dependence of the photoreaction and ESR studies under in situ
photolysis conditions ; the results provide some insight into
the effect of charge transfer on the selectivity of this photoreaction.
Preparative irradiation (A.= 400-500 nm) of 1 : 1 mixtures of 1 and 2 (concentration: 0.1-0.5 mol/L) in cyclohexane or benzene results in formation of the cycloadducts
3-5 and the reduction products 6-8 in 50-70% isolated
yields. The product ratio depends strongly on the structure
and electron donor abilities of 2 :
1. Only dioxoles containing allylic H atoms (2c, d) form
reduction products;
3a
3b
3c
R'=R2=H
R'=CH3,R2-H
R'rH, R2-CH3
6a
6b
R'= HI R2= CH3
4
7,8 (threo.erythro)
R'-R2=CH3
2. A decrease in oxidation potential (ET;J results in increased formation of reduction products, for example
@reduction/@addition = 0.07/0.08 (0.221 < 0.02) for 1
2c
(2d);
3. 1,4-Addition is only observed in the reaction of 2a with
1 ; thereby the dihydrodioxin 5 is formed
(3a:4a:5=1.2:1:1.1 in benzene).
+
It is noteworthy that photoreactions under S1- and TIconditions yield the same products in the same ratio;
neither varying the concentration of 2 (0.05-500 mmol/L,
see luminescence quenching rate constants (Fig. 1)) nor
sensitizating 1 by addition of benzophenone had any effect on the result[61.
Figure 1 illustrates that charge transfer is important in
the luminescence quenching of 116'. However, plots of
Igk,/E'& with slopes ca. 1/3 of that expected for full elec-
0 Verlag Chemie GmbH, 0-6940 Weinheim, 1984
0570-0833/84/0303-0249 $ 02.50/0
249
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diastereoselective, pivaloyl, tetrahydroisoquinoline, hydroxyalkylation, magnesium, via, derivatives, positional
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