Phosphine oxides cyclopropyl

C. Reactions not involving P=0 or P=S Groups.—Enamine phosphine oxides (45) have been prepared by the addition of amines to 1-alkynyl-phosphine oxides, and the reactions of their anions with various electrophiles have been reported. - With ketones a Wittig-type reaction leads to the formation of a/3-unsaturated ketones, in 53—70% yield, while with epoxides cyclopropyl ketimines are formed. A Diels-Alder reaction of l-phenyl-A -phospholen-l-oxide (46) with 1,4-diacetoxybutadiene has been used in the preparation of l-phenyl-benzo[/>]phosphole (47), as... 

EIimination of phosphine oxide with stereocontrol enables synthesis of optically active cyclopropyl ketones. ... 

The stereochemical course of the highly diastereoselective conversion of -keto y -hydroxy phosphine oxides (45) and related silylated derivatives (44) into cyclopropyl ketones, predominantly isomer (47), by treatment with Bu OK-Bu OH has been determined and used to synthetic advantage. ... 

Enamine phosphine oxides (159) seem suitable reagents for the preparation of ajS-unsaturated ketones, and of cyclopropyl ketones (Scheme 77). 

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