TETRAZOLE-FRAGMENTATION FOR THE GENERATION OF ALKYLIDENE CARBENES FROM CYANOPHOSPHATES UNDER NEUTRAL CONDITIONS AND ITS APPLICATION TO ORGANIC SYNTHESIS

The generation of alkylidene carbenes through tetrazole-fragmentation from cyanophosphates (CPs) under neutral conditions and its application to synthesis are reviewed. The following topics are covered: 1) The formation of alpha-azidotetrazoles and their transformation into alkynes under microwave heating conditions, 2) the transformation of carbonyl compounds into homologous via CPs, 3) the synthesis of five-membered unsaturated cyclic compounds from ketones via CPs, 4) the synthesis of C4-linked C-n-triazole ribonucleoside phosphoramidites from (beta-ribofuranosyl-C-n-acetylenes, and 5) the synthesis of (-)-neplanocin A and one of its important synthetic intermediates using cyclopentene-formation from CPs.