SYNTHESIS AND PROTODESILYLATION OF HETERO CYCLIC ALPHA-ALLENYLSILANES

Some psi-functional propargylic-bis-trimethylsilanes, easily prepared from propargyltrimethylsilane through classical methods, allow a conve nient one-pot synthesis of kyl-4-trimethylsilyl-3-vinylidenetetrahydro pyranes and N-alkyl-4-trimethylsilyl-3-vinylidene-piperidines. These n ew silanes undergo a protodesilylation reaction leading to conjugated heterocyclic dienes.