Asymmetric Reductive Carbocyclization Using Engineered Ene Reductases
作者:Kathrin Heckenbichler、Anna Schweiger、Lea Alexandra Brandner、Alexandra Binter、Marina Toplak、Peter Macheroux、Karl Gruber、Rolf Breinbauer
DOI:10.1002/anie.201802962
日期:2018.6.11
bearing an electron‐withdrawing group, for example, a carbonyl group. This asymmetricreduction has been exploited for biocatalysis. Going beyond its canonical function, we show that members of this enzyme family can also catalyze the formation of C−C bonds. α,β‐Unsaturated aldehydes and ketones containing an additional electrophilic group undergo reductive cyclization. Mechanistically, the two‐electron‐reduced
Syntheses of Seven-Membered Rings: Ruthenium-Catalyzed Intramolecular [5+2] Cycloadditions
作者:Barry M. Trost、Hong C. Shen、Daniel B. Horne、F. Dean Toste、Bernhard G. Steinmetz、Christopher Koradin
DOI:10.1002/chem.200401065
日期:2005.4.8
The Ru-catalyzed intramolecular [5+2] cycloaddition of cyclopropylenynes is investigated with respect to the regio- and diastereoselectivity as well as the functional group compatibility of the reaction. Evidence for the mechanism as occurring through a ruthenacyclopentene intermediate is elucidated from 1) the study of the diastereoselectivity of the cycloaddition; 2) the effect of variation of substituents
We have developed a versatile method for the synthesis of enantiomerically pure cis-2-methylcyclopropanecarboxylic acid (−)-2, a component of curacin A, and its enantiomer, (+)-2. Double-asymmetric Simmons-Smithcyclopropanation of the dienes 5 and 9 derived from diethyl L-tartrate proceeded with excellent diastereofacial selectivity (>99% de) to give the dicyclopropanes 6 and 10, which were converted
Easy to N‐cycle: The efficient synthesis of azepinederivatives was achieved by Rh‐catalyzed tandem 2,3‐rearrangement involving the heterocyclization of N‐allenylnitrone intermediates (see scheme; cod=1,5‐cyclooctadiene, tppms=sodium diphenylphosphinobenzene‐3‐sulfonate).