Exo selective diels-alder reactions mediated by Et2AlCl in the presence of H2O
摘要:
Diels-Alder reactions of 4-triisopropylsilyloxy-2H-thiopyran with N-(2-propenoyl)-2-oxazolidones are promoted by Lewis acids. Unusually high exo selectivity is observed when Et2AlCl in the presence of H2O is used as the Lewis acid. The involvement of the sulfur atom with the bidentate Lewis acid dichlorodiethyl-mu-oxodialuminum is postulated.