Synergistic Lewis base and anion-binding catalysis for the enantioselective vinylogous addition of deconjugated butenolides to allenoates
作者:Vikas Kumar、Santanu Mukherjee
DOI:10.1039/c3cc46858e
日期:——
An enantioselective vinylogous umpolung addition of deconjugated butenolides to allenoates has been developed for the first time with the help of synergistic combination of an achiral phosphine and a chiral squaramide, and represents the first example of a catalytic enantioselective Cγ–Cγ bond formation between two different carbonyl partners.
Resolution of (±)-3-methylmuconolactone and the absolute configurations of the naturally occurring 3- and 4-methylmuconolactones: X-ray crystal structures of (S)-1-phenylethylammonium salts and a bromodilactone
作者:Ronald B. Cain、Andrew A. Freer、Gordon W. Kirby、Ghanokota V. Rao
DOI:10.1039/p19890000202
日期:——
(%)-3-Methylmuconolactone (4c) has been resolved via the diastereoisomeric salts of (S)-(–)-1-phenylethylamine and the absoluteconfigurations of fungal (4S)–(-)-3-methylmuconolactone (6) and bacterial (4S)-(+)-4-methylmuconolactone (9) have been determined by combined use of X-ray crystallographic analysis and chemical correlation.