Reactions of iron carbonyls with ylides

Abstract

Phosphoranes having the structure p-XC 6H 4CHP(C 6H 5) 3 [where X = H, CH 3, OCH 3] react with iron carbonyls in dry tetrahydrofuran to give low-reasonable yields of stilbenes as well as unstable purple-red organometallic complexes, triphenylphosphineiron tetracarbonyl, and triphenylphosphine oxide. Most phosphoranes of type RCHP(C 6H 5) 3 [R = alkyl] also formed unstable organometallics and (C 6H 5) 3PFe(CO) 4, but only in two instances were the substituted ethylenes isolated in low yields. Substantial variation in the cis-trans alkene distribution and in the overall yield of alkene was observed in the reaction of Fe(CO) 5 with p-CH 3C 6H 4CHP(R′) 3, where R′ = p-FC 6H 4, C 6H 5, n-C 4H 9, and (CH 3) 2N. The reaction of Fe(CO) 5 with C 6H 5COCH −M +, where M + = P +(C 6H 5) 3, P +( p-FC 6H 4) 3, N +C 5H 5, and S +(CH 3) 2, and several other stable ylides was also investigated.