反应详情

The procedure is as in Example 2 for the preparation of N-(3-ethoxy-3-ethoxycarbonylpropenylidene)-N-methylmethanaminium tetrafluoroborate, starting with t-butyl 4-dimethylamino-2-oxo-3-butenoate (3.3 g) and triethyloxonium tetrafluoroborate (3.62 g) in dichloromethane (20 cc). The solution of N-(3-ethoxy-3-t-butyloxycarbonylpropenylidene)-N-methylmethanaminium tetrafluoroborate in methylene chloride thereby obtained is stored under an argon atmosphere and used immediately in the subsequent syntheses.