The cobalt way to vitamin B6. Regioselective construction of the tetrasubstituted pyridine nucleus by cobalt-catalyzed alkyne-nitrile cooligomerizations

Article abstract of DOI:10.1016/S0040-4020(01)91418-8

Cocyclization of bis(trimethylsilyl)- and bis(trimethylstannyl)di-2-propynyl ether with acetonitrile provides a synthetic entry into 1,3-dihydro-6-methyl-4,7-bis(trimethylsilyl)- and bis(trimethylstannyl)-furo[3,4-c]pyridines. Regioselective electrophilic substitution of the respective silyl or stannyl groups allows for a regiocontrolled construction of tetrasubstituted pyridines. This method has been applied to a total synthesis of vitamin B₆.