Stereoselective synthesis of 3-spiro-α-methylene-γ-butyrolactone oxindoles from Morita–Baylis–Hillman adducts of isatin
作者:Ponnusamy Shanmugam、Vadivel Vaithiyanathan
DOI:10.1016/j.tet.2008.02.002
日期:2008.4
concise stereoselective synthesis of 3-spiro-α-methylene-γ-butyrolactone oxindoles from Morita–Baylis–Hillmanadducts of isatin in excellent yield has been achieved following a three-step reaction sequences viz. (1) Isomerisation of the Morita–Baylis–Hillmanadducts of isatin with trimethyl orthoformate and montmorillonite K10 clay catalyst, (2) a second Morita–Baylis–Hillman reaction with formaldehyde