Enantioselective Organo-Singly Occupied Molecular Orbital Catalysis: The Carbo-oxidation of Styrenes
作者:Thomas H. Graham、Casey M. Jones、Nathan T. Jui、David W. C. MacMillan
DOI:10.1021/ja8075633
日期:2008.12.10
The first enantioselective organocatalytic carbo-oxidation of styrenes has been accomplished using singly occupied molecular orbital (SOMO) catalysis. Geometrically constrained radical cations are generated from the one-electron oxidation of enamines formed from the condensation of aldehydes with a secondaryamine catalyst. These SOMO-activated radical cations are susceptible to attack by commercially
Enantioselective Linchpin Catalysis by SOMO Catalysis: An Approach to the Asymmetric α-Chlorination of Aldehydes and Terminal Epoxide Formation
作者:Muriel Amatore、Teresa D. Beeson、Sean P. Brown、David W. C. MacMillan
DOI:10.1002/anie.200901855
日期:2009.6.29
Time for SOme MOre: For the first time SOMO (singly occupied molecular orbital) activation has been exploited to allow a new approach to the α‐chlorination of aldehydes. This transformation can be readily implemented as part of a linchpincatalysisapproach to the enantioselective production of terminalepoxides.
SOme MOre 时间:首次利用 SOMO(单占据分子轨道)激活来实现醛的 α-氯化的新方法。这种转化可以很容易地作为对映选择性生产末端环氧化物的关键催化方法的一部分来实现。
Enantioselective α-Alkylation of Aldehydes by Photoredox Organocatalysis: Rapid Access to Pharmacophore Fragments from β-Cyanoaldehydes
作者:Eric R. Welin、Alexander A. Warkentin、Jay C. Conrad、David W. C. MacMillan
DOI:10.1002/anie.201503789
日期:2015.8.10
The combination of photoredox catalysis and enamine catalysis has enabled the development of an enantioselective α‐cyanoalkylation of aldehydes. This synergistic catalysis protocol allows for the coupling of two highly versatile yet orthogonal functionalities, allowing rapid diversification of the oxonitrile products to a wide array of medicinally relevant derivatives and heterocycles. This methodology
Nickel‐Catalyzed Negishi Cross‐Couplings of Secondary Nucleophiles with Secondary Propargylic Electrophiles at Room Temperature
作者:Sean W. Smith、Gregory C. Fu
DOI:10.1002/anie.200802784
日期:2008.11.17
Spin-Center Shift-Enabled Direct Enantioselective α-Benzylation of Aldehydes with Alcohols
作者:Eric D. Nacsa、David W. C. MacMillan
DOI:10.1021/jacs.7b12768
日期:2018.3.7
two-electron pathways. We report herein an enantioselective α-benzylation of aldehydes using alcohols as alkylating agents based on the mechanistic principle of spin-center shift. This strategy harnesses the dual activation modes of photoredox and organocatalysis, engaging the alcohol by SCS and capturing the resulting benzylic radical with a catalytically generated enamine. Mechanistic studies provide
大自然通常使用醇作为离去基团,因为 DNA 生物合成依赖于通过自由基介导的“自旋中心转移”(SCS)机制从核糖核苷二磷酸中去除水。然而,由于醇在双电子途径中的低反应性,醇在合成化学中作为烷化剂仍然没有得到充分利用。我们在此报告了基于自旋中心位移的机械原理,使用醇作为烷化剂的醛的对映选择性 α-苄基化。该策略利用光氧化还原和有机催化的双重激活模式,通过 SCS 与醇结合,并用催化生成的烯胺捕获产生的苄基自由基。机理研究为 SCS 作为关键的基本步骤提供了证据,确定了竞争反应的起源,