A Practical Method for the Separation of E/Z-Isomeric Silyl Enol Ethers by Kinetic Resolution
17 September 2002 (online)
E/Z-Isomeric silyl enol ethers 1 (1-trimethylsiloxy-1-alkenes) can be separated by cycloaddition to nitrosostyrene (2), which allows recovery of unconsumed isomerically pure (Z)-1. On the other hand, the high selectivity of diphenylketene (5) can be exploited to trap Z silyl enol ethers and to reisolate pure (E)-1. The simple procedures make available gram quantities of both isomers in pure state.