Stereoselective synthesis and structure of butalactin and lactone II isolated from Streptomyces species
作者:Toshihiko Ueki、Takamasa Kinoshita
DOI:10.1039/b407820a
日期:——
Butalactin (1a) and lactone II (2a) have been synthesized starting from (S)-malic acid and sorbic acid by a straightforward route. The absolute stereochemistry of 1a and 2a was unambiguously established by this synthesis.
Very high chemoselective, regioselective, and E-stereoselective 1,3-chirality transfer involving reaction of acyclic (E)- and (Z)-.gamma.-mesyloxy .alpha.,.beta.-enoates and organocyanocopper-trifluoroborane reagents. Efficient synthetic routes to functionalized chiral .alpha.-alkyl (E)-.beta.,.gamma.-enoates and (E)-allylic alcohols with high optical purity
Remarkable difference in reactivity of ordinary vinylcopper reagents and vinylzinc halide containing a copper salt towards γ-mesyloxy-α, β-enoates. Synthesis of homochiral 1,4-dienes
Whereas the reaction of gamma-mesyloxy alpha,beta-enoates with vinyl-Cu(CN)M or (vinyl)2Cu(CN)M2 (M = Li or MgX) yielded a reduction product with an (E)-double bond at the beta,gamma-position, treatment of the same substrates with ''higher order'' zinc cuprate reagents or vinyl-ZnCl by the addition of catalytic amount of Cu(I) or Cu(II) salt afforded alpha- and gamma-vinylation products. Both vinylation products were stable 1,4-diene derivatives that are only more difficulty accessed by more traditional means.