A Facile Method for the Stereoselective Horner-Wadsworth-Emmons Reaction of Aryl Alkyl Ketones.

Abstract

Excellent Z or E selectivity was observed in the Horner-Wadsworth-Emmons (HWE) reactions of methyl bis(2,2,2-trifluoroethyl)phosphonoacetate or ethyl 2-fluoro-2-diethylphosphonoacetate with aryl alkyl ketones bearing substituents on an aromatic moiety employing Sn(OSO 2 CF 3 ) 2 in the presence of N-ethylpiperidine.

Pyrrolidine-Mediated Direct Preparation of (E)-Monoarylidene Derivatives of Homo- and Heterocyclic Ketones with Various Aldehydes

“…Thus, the synthesis of these compounds has attracted increasing attention from chemists, biochemists and pharmacologists. So far, several strategies are reported for the preparation of these compounds, which are accomplished by various methods such as condensation, oxidation, elimination, acylation, and insertion of carbon monoxide, among others [7][8][9][10][11][12][13][14][15]. In connection with a project in our laboratory, we required mono-2-arylidene derivatives of ketones, particularly of piperidone.…”

Cationic Rhodium(I)‐Catalyzed Asymmetric Cyclohydroformylation of 1,6‐Enynes with Formaldehyde

“…[21] Compound 2 a also could reacted with NaBH 4 in the presence of N-allylamine to produce the enantiomerically enriched amine 4 b in 87% yield with 98% ee (b). [22] Even when 2 a was reacted with a more basic Grignard reagent, phenylmagnesium bromide, [23] no racemization of 2 a and/or products occurred and a diastereomeric mixture with phenylated formyl groups was obtained in a diastereomeric ratio of 85/15 (c). The expression of this diastereoselectivity could be easily considered as follows.…”

Stereoselective Synthesis of Tetrasubstituted (Z)-Alkenes from Aryl Alkyl Ketones Utilizing the Horner-Wadsworth-Emmons Reaction.

“…[4][5][6][7][8] While a number of methods have been developed for the stereoselective synthesis of alkenes, few accounts have appeared in the literature describing the convenient preparation of tetrasubstituted (Z )-alkenes with excellent selectivity. [9][10][11][12][13] We have already presented a facile method for obtaining tetrasubstituted (E )-fluoroalkenes.…”