High Chelation Control of Three Contiguous Stereogenic Centers in the Reformatsky Reactions of Indium Enolates with α-Hydroxy Ketones: Unexpected Stereochemistry of Lactone Formation

A boat-type of chelated bicyclic transition state involving highly diastereoselective construction of three contiguous stereogenic centers in
the Reformatsky reaction of indium enolates with α-alkoxy/hydroxy ketones is proposed. α-Hydroxy ketones with indium enolates furnished
highly diastereoselective lactones, while α-alkoxy ketones gave acyclic esters in moderate selectivities. X-ray structure analyses of key products
unequivocally revealed the unexpected stereochemistry of products and the reaction pathway.