Alkene prodn. from hydroxy:methane phosphonate - and e.g. phosphonium salt, esp. for producing styryl-cyclopropane pyrethrin intermediates

摘要

Prodn. of alkenes of formula (I) comprises reacting the phosphonate (II) with P-contg. reagents (III) in presence of base at -70 to 150 degrees C. Opt. reaction is also in presence of diluents and catalysts. (R1=opt. substd. alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aralkyl, aralkenyl, aryl or heterocyclyl. R2=H or halo, R3=halo, CN or opt. substd. alkyl, alkenyl, alkynyl, cycloalkyl, aralkenyl, aryl, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aminocarbonyl or heterocyclyl. R4= alkyl or phenyl, or 2 together make an opt. branched alkylene. Z is -P(O)R5R6 or -P(R7)3 +X-. R5 and R6 = alkyl, phenyl, alkoxy or phenoxy, or together alkanedioxy. R7 = alkyl or phenyl. X=halo). (I) are useful e.g. as intermediates for insecticidal pyrethroid. The method is simple, inexpensive, uses readily available starting materials (esp. there is no need to prepare aldehydes) and gives high yields of pure prod. Reaction is at about room temp. and requires only inexpensive aq. bases.