Tandem Chain Extension-Iodomethylation Reactions: Formation of alpha-Functionalized gamma-Keto Carbonyls.

Sequential exposure of a zinc-organometallic intermediate, generated through a zinc carbenoid-mediated chain extension reaction of a beta-keto carbonyl, to trimethylsilylchloride and iodine provided regioselective formation of an alpha-iodomethyl-gamma-keto carbonyl. The iodomethyl functionality can be further manipulated to provide side chains that are potential mimics of alpha-amino acid side chains.