Selective Addition of Organolithium Reagents to BF2-Chelates of β-Ketoesters

A short, mild, and highly chemoselective addition of organolithium reagents to a BF2 complex of 3-oxopropanoates has been developed. The methodology allows straightforward preparation of various 1,3-dioxa-BF2 complexes and subsequently leads to the formation of 1,3-diketones starting from the corresponding 3-oxopropanoates.