Semi‐Rationally Designed Short Peptides Self‐Assemble and Bind Hemin to Promote Cyclopropanation
作者:Oleksii Zozulia、Ivan V. Korendovych
DOI:10.1002/anie.201916712
日期:2020.5.18
amyloid assemblies can impart a substantial degree of enantioselectivity without the need for extensive optimization; 3. The ease of peptidepreparation allows for straightforward incorporation of unnatural aminoacids and preparation of peptides made of D-amino acids with complete reversal of enantioselectivity.
addition of the very reactive metallacarbene intermediate in an early transition state to the substrate alkene is concerted but strongly asynchronous, with substantial cationic character on one alkene carbon in the neighborhood of the transition state. Evidence from isotope effects and Hammett studies supports the nature of the transition state. Formation of a metallacyclobutaneintermediate by a [2+2] addition
Diastereoselective and Enantioselective Cyclopropanation of Alkenes Catalyzed by Cobalt Porphyrins
作者:Lingyu Huang、Ying Chen、Guang-Yao Gao、X. Peter Zhang
DOI:10.1021/jo035088o
日期:2003.10.1
catalysts for selective cyclopropanation of alkenes with ethyl diazoacetate (EDA). The catalytic system can operate with alkenes as limiting reagents, requiring only stoichiometric amounts of EDA. The protocol is performed in one-pot fashion without the need of slow addition of EDA. The diastereoselectivity of the current system can be tuned by using different porphyrin ligands or additives, giving either
Chemoselective Cyclopropanation over Carbene Y–H Insertion Catalyzed by an Engineered Carbene Transferase
作者:Eric J. Moore、Viktoria Steck、Priyanka Bajaj、Rudi Fasan
DOI:10.1021/acs.joc.8b00946
日期:2018.7.20
biocatalysts for promoting a variety of carbene transfer reactions including cyclopropanation and Y–H insertion (Y = N, S, Si, B). For these and synthetic carbene transfer catalysts alike, achieving high chemoselectivity toward cyclopropanation in olefin substrates bearing unprotected Y–H groups has proven remarkably challenging due to competition from the more facile carbene Y–H insertion reaction. In this
Highly Diastereoselective and Enantioselective Olefin Cyclopropanation Using Engineered Myoglobin-Based Catalysts
作者:Melanie Bordeaux、Vikas Tyagi、Rudi Fasan
DOI:10.1002/anie.201409928
日期:2015.2.2
Using rational design, an engineered myoglobin‐based catalyst capable of catalyzing the cyclopropanation of aryl‐substituted olefins with catalytic proficiency (up to 46 800 turnovers) and excellent diastereo‐ and enantioselectivity (98–99.9 %) was developed. This transformation could be carried out in the presence of up to 20 g L−1 olefin substrate with no loss in diastereo‐ and/or enantioselectivity
通过合理的设计,开发了一种工程化的基于肌红蛋白的催化剂,该催化剂能够催化芳基取代的烯烃的环丙烷化,具有催化能力(高达46 800次营业额)和出色的非对映和对映选择性(98–99.9%)。该转化可在不超过20 g L -1烯烃底物的存在下进行,且非对映选择性和/或对映选择性不损失。诱变和机理研究支持由亲电的血红素结合的卡宾物质介导的环丙烷化机理,并提供了一个模型来合理化蛋白质催化剂的立体偏好。这项工作表明,肌红蛋白是开发具有卡宾转移反应性的生物催化剂的有前途和强大的支架。