Cobalt-mediated synthesis of highly crowded steroids: unusual observations of hindered rotation of a trimethylsily group
Abstract
(η5-C5H5)Co(CO)2 catalyses the [2 + 2 + 2] cycloaddition of silylated enediynes to furnish 1-trimethylsilyl and 1,11-bis(trimethylsilylated) A-ring aromatic steroids which unexpected hindered rotation of the trimethylsilyl groups.