Synthesis of Fischer-type (alkoxy)carbene complexes using diphenylsulfonium salts with functionalized alkyl groups

A new and general method for preparing Fischer-type alkoxycarbene complexes 1 is reported. This method involves the alkylation of acylate complexes 7 with alkyldiphenylsulfonium salts 10 with a variety of functionalized alkyl groups. The alkylation of tetramethylammonium pentacarbonyl(1-oxyalkyliden e)chromate(0) 7a-c, tetramethylammonium pentacarbonyl(1-oxymethylidene)moly bdate(0) 7d, and pentacarbonyl(1-oxymethylidene)tungstate 7e with alkyldiph enylsulfonium salts 10 proceeded smoothly under mild conditions to give the corresponding alkoxycarbene complexes 12-39 in good to high yields. Compet itive alkylation of 7a with. methyl-11 and isopropyldiphenylsulfonium tetra fluoroborate 40 shows a higher reactivity of the isopropyl group, suggestin g the participation of an S-O sulfurane intermediate 41.