Alkene prodn. from alpha-hydroxy phosphonate - and phosphonate or phosphonium salts, useful as intermediates for pyrethroid insecticides

摘要

(A) The following process is new: base right arrow opt. catalyst opt. diluent -70 to +150 degrees C (R1 is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aralkyl, aralkenyl, aryl or heterocyclyl, all opt. substd; R2 is H or halogen; R3 is halogen, CN or an opt. substd. alkyl, alkenyl, alkynyl, cycloalkyl, aralkenyl, aryl, alkanoyl, aroyl, alkoxycarbonyl, carbamoyl or heterocyclyl gp.; R4 is alkyl or phenyl, or the two R4 gps. together are alkylene; Z1 is P(O)R5R6 or P(R7)3 + X-; R5 and R6 are each alkyl, phenyl, alkoxy or phenoxy, or together are alkylenedioxy; R7 is alkyl or phenyl; X is halogen). (I), esp. 3-(2-chloro-2-phenyl-vinyl)-2,2-dimethyl-cyclopr opane 1-carboxylic acid esters, and (XI) are intermediates for pyrethroid insecticides and acaricides. (I) can be prepd. in high yield and purity, in a reaction at (or near) room temp., in presence of cheap bases (e.g. alkali metal hydroxides or alcoholates) and water-contg. solvents (c.f. usual Wittig conditions), without using difficult-to-obtain aldehyde intermediates.