Enantioselective bromolactonization of cis-1,2-disubstituted olefinic acids using an amino-thiocarbamate catalyst
作者:Chong Kiat Tan、Chencheng Le、Ying-Yeung Yeung
DOI:10.1039/c2cc31148h
日期:——
A facile, highly regio- and enantioselective amino-thiocarbamate-catalyzed bromolactonization of cis-1,2-disubstituted olefinicacids has been developed. The use of the enantio-enriched lactones in the synthesis of chiral synthetic intermediates is also demonstrated.
Enantioselective Bromocycloetherification by Lewis Base/Chiral Brønsted Acid Cooperative Catalysis
作者:Scott E. Denmark、Matthew T. Burk
DOI:10.1021/ol203033k
日期:2012.1.6
A binary catalyst system for the enantioselective bromocycloetherification of 5-arylpentenols is described. The combination of an achiral Lewis base and a chiralBrønstedacid affords good enantioselectivities for the cyclization of Z configured 5-arylpentenols to form bromomethyltetrahydrofurans. The constitutional site selectivity is highly dependent upon the aromatic substituent and the configuration
alkenyl C–H allylation by an exo-palladacycle intermediate is demonstrated, employing unactivated (Z)-alkenes and allyl carbonates. With the use of an 8-aminoquinoline (AQ) derived amide as the directing group, the N,N-bidentate-chelation-assisted C–H activation protocol proceeded under mild and oxidant-free conditions with excellent selectivity. The utility of this approach is demonstrated by the preparative