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
Totalsynthesis of curacin A, a novel antimitotic antiproliferative antibiotic, was achieved by the connection of C1C7, C8C17, and C18C22 segments. Enantioselective preparation of each segments were accomplished by asymmetric allylation, chiral synthon method, and asymmetric hydrolysis by using pig liver esterase, respectively.
Absolute configuration of curacin A, a novel antimitotic agent from the tropical marine cyanobacterium Lyngbya majuscula
作者:Dale G. Nagle、Robin S. Geralds、Hye-Dong Yoo、William H. Gerwick、Tae-Seong Kim、Mitch Nambu、James D. White
DOI:10.1016/0040-4039(95)00030-g
日期:1995.2
Curacin A is a structurally novel antimitotic agent isolated from the Caribbean cyanobacterium Lyngbyamajuscula. Its planar structure has been previously determined from a spectroscopic investigation. Here, we define the complete relative and absolute configuration of curacin A by comparison of products obtained from chemical degradation of the natural product with the same substances prepared by
Charette asymmetric cyclopropanation, chiral thiazoline synthesis by thioamide cyclization under modified Mitsunobu conditions, Ti(iPrO)4/bi-naphthol catalyzed allylstannane addition, and an exceptionally mild two-carbon homologation via dehydrative alkylation with phenylsulfonylacetonitrile/Ph3P/ADDP convened in an efficient, stereocontrolled route to the title bioactive heterocycle.
Charette不对称环丙烷化,在改良的Mitsunobu条件下通过硫酰胺环化反应合成手性噻唑啉,Ti(i PrO)4 /双萘酚催化烯丙基锡烷的加成,以及通过苯烷基磺酰乙腈/ Ph 3 P / ADDP的脱水烷基化产生的异常温和的二碳同系物标题生物活性杂环的高效,立体控制路线。