Synthesis of 3-alkylpyridines. Part 2. Synthesis of both enantiomers of niphatesine C2
Both enantiomers of the pyridine alkaloid niphatesine C 1 have been prepared in a convergent synthesis by acylation of the nonracemic thiophenes 3 and ent-3, reductive desulfurization, and functional group transformation. The absolute configuration of the natural product was established as (S) based on comparison of the sense of optical rotation with that of synthetic 1.