Asymmetric Methoxyselenenylation of Alkenes with Chiral Ferrocenylselenium Reagents

Asymmetric methoxyselenenylation of alkenes was studied using some chiral ferrocenylselenium compounds which were prepared from chiral ferrocenyl-substituted amine, sulfoxide, oxazoline, and pyrrolidine. The highest diastereoselectivity was observed using the chiral amino-substituted ferrocenylserenium triflates in the reaction with trans -β-methylstyrene in an excellent yield. The reaction with silyl enol ethers gave chiral α-seleno ketone with moderate to excellent selectivities. The β,γ-unsaturated ester may be converted into the optically active γ-alkoxy α,β-unsaturated ester using ammonium persulfate in the presence of a catalytic amount of the chiral diferrocenyl diselenide in low optical yields.