Syntheses and Stereochemical Assignment of Toxic C17-Polyacetylenic Alcohols, Virols A, B, and C, Isolated from Water Hemlock (Cicuta virosa).

Abstract In the course of our study on neurotoxic C 17 -polyacetylenic alcohols of the toxic plant, Cicuta virosa , virols A ( 1 ), B ( 2 ), and C ( 3 ) were synthesized by stereoselective routes to confirm their stereochemistry and to obtain supply of these compounds for pharmacological study. The syntheses used chiral 3-hydroxy-1-alkyne building blocks, Pd(0)-CuI(I)-catalyzed coupling of acetylene with vinyl chloride, and heterocoupling reaction of acetylene mediated by CuI. As a result, the absolute configuration of the stereogenic center of virols A ( 1 ), B ( 2 ), and C ( 3 ) was confirmed as S , S , and S , respectively.