Convenient synthesis of (triphenyl)germyl and (triphenydstannyl substituted allenes

Abstract

Allenyl-germanes and -stannanes, Ph3MC(R)=C=CR′R″ (M = Ge, Sn) can be obtained, generally in excellent yield, through alkylcopper(I)-induced 1,3-substitution of the propargylic chlorides Ph3MCCCR′R″Cl. In the tin series, however transmetallation is the main process when MeCu, H2C=CHCu or PhCu are used. The allenyl compounds in which R is (trimethylsilyl)ethynyl or 4,4-dimethyl-1,2-pentadienyl can be obtained by using the organozinc compounds instead of the copper(I) compound and using tetrakis(triphenylphosphine)palladium as catalyst.