Synthesis of α-silylalkylbenzoxazoles and oxazoles from stable silylketenes

Stable silylketenes, prepared by rhodium-catalysed decomposition of silyldiazoketones, undergo addition/cyclocondensation sequences with aminophenols and aminomalonate to give α-silylalkylbenzoxazoles and oxazoles, respectively. The silicon can be retained throughout functional group interconversions or can be removed by protodesilylation under acidic conditions as desired.