Alkylation of 2-oxy-substituted 1-sulfonylallyl and 1-sulfonylvinyl anions. New routes to functionalized carbocycles and dihydrofurans
作者:Albert Padwa、William H. Bullock、Andrew D. Dyszlewski、S. W. McCombie、B. B. Shankar、A. K. Ganguly
DOI:10.1021/jo00011a021
日期:1991.5
Alkylation of the anion derived from 2-phenoxy-3-(phenylsulfonyl)-1-propene proceeds alpha to the phenylsulfonyl group and affords cyclic products from 1,omega-dihalides. Reaction of the monoalkylated products, in which a suitably positioned olefinic or acetylenic unit is present, with sodium benzenesulfinate-acetic acid gives functionalized acetylcyclopentenes and cyclohexenes via C-C bond formation from the allyl cation-sulfinate ion pair. In the vinyl sulfone series, deprotonation of (E)- or (Z)-2-alkoxyvinyl phenyl sulfones rapidly affords the more stable (E)-lithio derivative, an acetaldehyde anion equivalent which reacts normally with aldehydes, ketones, alkyl halides, and epoxides. The latter process may be effected in an intramolecular fashion. Thus, (E)-(2-phenylsulfonyl) vinyl ethers of 2,3-epoxy alcohols cyclize on treatment with amide bases to afford dihydrofurans whose stereochemistry is fully defined by that of the starting epoxy alcohol.