Enantioselective Bromolactonization of Conjugated (Z)-Enynes
摘要:
A catalytic enantioselective syn-1,4-bromolactonization of conjugated (Z)-enynes was reported. Diastereomeric ratios >20:1 and up to 99% enantiomeric excesses were observed. Di-, tri-, and tetra-substituted bromoallenes were prepared together with lactone heterocycles efficiently and stereoselectively, Preliminary investigations Suggest that the chiral catalyst may serve as a bifunctional reagent by interacting with both a carboxylic acid nucleophile and NBS electrophile.
Enantioselective Bromolactonization of Conjugated (<i>Z</i>)-Enynes
作者:Wei Zhang、Suqing Zheng、Na Liu、Jenny B. Werness、Ilia A. Guzei、Weiping Tang
DOI:10.1021/ja100173w
日期:2010.3.24
A catalytic enantioselective syn-1,4-bromolactonization of conjugated (Z)-enynes was reported. Diastereomeric ratios >20:1 and up to 99% enantiomeric excesses were observed. Di-, tri-, and tetra-substituted bromoallenes were prepared together with lactone heterocycles efficiently and stereoselectively, Preliminary investigations Suggest that the chiral catalyst may serve as a bifunctional reagent by interacting with both a carboxylic acid nucleophile and NBS electrophile.
Catalytic Enantioselective Halolactonization of Enynes and Alkenes
作者:Wei Zhang、Na Liu、Casi M. Schienebeck、Kyle Decloux、Suqing Zheng、Jenny B. Werness、Weiping Tang
DOI:10.1002/chem.201103809
日期:2012.6.4
developed for the enantioselectivehalolactonization of (Z)‐1,3‐enynes and 1,1‐disubstituted alkenes. In the case of 1,3‐enynes, the carboxylate nucleophile and halogen electrophile were added to the conjugated π‐system from the same face. Up to 99 % ee was achieved for the 1,4‐syn‐bromolactonization of conjugated (Z)‐1,3‐enynes. Based on the results from the enynehalolactonization, a second generation