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New Methods for the Alkylation of Carbonyl Compounds.

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31P-NMR (30% solution in C,Hl,, H,PO, external
standard): 6 = -4.1 ( 5 a j , -3.8 ( 5 b j ppm, 'JpH=587.7,
'JpD=90.0, 35Hp=13.5 ( 5 a , b ) Hz.
Experimental:
PF2N(SiR3)2 (85g, 0.37mol) was added dropwise to a
stirred suspension of Li(NSiR3), (100g, 0.6mol) in light
petroleum (b. p. G 6 0 "C)at room temperature in a 500-ml
three-necked flask fitted with a reflux condenser and dropping funnel. After 3 hours' stirring, most of the solvent
was removed and the residue was fractionally distilled
under reduced pressure. The fraction passing over at 50
to 60 C/O.Ol torr was freed from residual P F Z N ( S ~ R ~ ) ~
by being kept for 20h at room temperature and 0.01
torr. Redistillation gave pure (3) at 62-63 'C/O.OI torr
(yield 55 g, 53 %).
Received: December 6, 1972 [Z 793 I€]
revised: June 4, 1973
German version: Angew. Chem. XS, 586 ( I 973)
CONFERENCE REPORTS
New Methods for the Alkylation
of Carbonyl Compounds
By R. M . Coated']
Carbonyl compounds play a key role in organic synthesis,
particularly in the formation of new carbon-carbon bonds.
One such transformation, within the general class of nucleophilic alkylation reactions, is methylene (alkylidene)
transfer, a conversion usually effected by sulfonium ylides.
As in the case of the analogous methylenation reaction['],
we have found['] that the structural limitations on methylene transfer by ylides (steric hindrance and proton abstraction)may be substantially reduced by use of a three reaction
sequence originating with addition of phenylthiomethyllithium[31.A pertinent example is the efficient methylene
transfer to the sterically hindered and enolizable substrate,
benzyl tert-butyl ketone ( I ).
The regiospecific transformation of a quaternary-type 0keto ester to a quaternary alkyl ketone of type ( 4 ) may
be carried out through pyrolytic decarboxylation of trimethylsilyl p-keto esters ( 3 f ' ] to trimethylsilyl enol ethers
and subsequent enolate generation and alkylation.
These methods enhance the flexibility and scope of the
relatively few known methods['] for the regiospecific synthesis of x-quaternary ketones.
Lecture at Giessen, April 26, 1973 [VB 369 I€]
German version: Angew. Chem. 85. 630 (1973)
[I] R . L. Sowrrhj and R . M. C o u t r ~ ,J. Amer. Chem. Sot. 94, 4578
( 1972).
[2] A simultaneous and complementary investigation has been carried
out by C. R . Johnson and 1. R. Shunklin.
Electrophilic alkylation CI to carbonyl functions constitutes
an important method for creation of quaternary carbon
centers in synthesis. We have recently developed some
new procedures for regiospecific x-quaternization. By
means of the sequential operations of alkylation-reductionalkylation upon P-thioaryl ketones of type (2), overall
regiospecific geminal dialkylation of ketones may be
achieved.
.
~~
[*] Prof. Dr. R. M. Coates
Department of Chemistry
106 Noyes Laboratory
University of Illinois at
Urbana, 111. 61 801 (USA)
586
131 E. J . Core?. and D. Swbach, J. Org. Chem. 31, 4097 (1966).
[4] Y - N . K u o , J . A. Yuhncr, and C. Ainsworth. J. Amer. Chem. SOC.
Y3. 6321 (1971).
[S] R. M . Courrs and R. L. SOwrrhJ~,J. Amer. Chem. Sac. 93, I027
11971): D.J . Pusto and P. W Wojtkowski, J. Org. Chem. 36, 1790 (1971).
Studies on Methyleneimmonium Salts
By Heinrich Volz'']
Methyleneimmonium salts are of interest from both a
preparative and a mechanistic viewpoint. They have been
discussed as reactive intermediates in the following reactions: Mannich reaction; Leuckart-Wallach reaction;
Polonovski reaction: fragmentation of y-halo amines.
The methyleneimmonium salts ( I ) used in our studies
(perchlorates, tetrafluoroborates, and hexachloroanti-~
~~
[*] Prof. Dr. H. Volz
lnstitut fur Organische Chemie der Universitat
75 Karlsruhe, Richard-Willstatter-Allee (Germany)
Anyrw. Chem. internut. Edit.
/ Vol. 12 (1973) J No. 7
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