Stereoselectivity of Methyl Aryldiazoacetate Cyclopropanations of 1,1-Diarylethylene. Asymmetric Synthesis of a Cyclopropyl Analogue of Tamoxifen
摘要:
Dirhodium tetrakis(S(N-dodecylbenzenesulfonyl)prolinate) (Rh-2(S-DOSP)(4))-catalyzed decomposition of methyl phenyldiazoacetate in the presence of 1,1-diarylethylenes results in intermolecular cyclopropanation with high enantioselectivity (up to 99% ee) and moderate diastereoselectivity (up to 80% de). The reaction was applied to the asymmetric synthesis of a cyclopropyl analogue of tamoxifen.
The Concept of Photozymes: Short Peptides with Photoredox Catalytic Activity for Nucleophilic Additions to α‐Phenyl Styrenes
作者:Daniel Sack、Hans‐Achim Wagenknecht
DOI:10.1002/ejoc.202101068
日期:2021.12.14
Keep the substrate until “mission is completed”: The forward and backward electron transfer steps in a photoredoxcatalytic cycle are controlled substrate bindings to photocatalytically active peptides, the “photozymes”.
Nickel-Catalyzed Direct Synthesis of Aryl Olefins from Ketones and Organoboron Reagents under Neutral Conditions
作者:Chuanhu Lei、Yong Jie Yip、Jianrong Steve Zhou
DOI:10.1021/jacs.7b02742
日期:2017.5.3
Nickel-catalyzed addition of arylboron reagents to ketones results in aryl olefins directly. The neutral condition allows acidic protons of alcohols, phenols, and malonates to be present, and fragile structures are also tolerated.
Palladium-Catalyzed Coupling of Sulfonylhydrazones with Heteroaromatic 2-Amino-Halides (Barluenga Reaction): Exploring the Electronics of the Sulfonylhydrazone
作者:Hongyu Tan、Ioannis Houpis、Renmao Liu、Youchu Wang、Zhilong Chen、Matthew J. Fleming
DOI:10.1021/acs.oprd.5b00211
日期:2015.8.21
paper describes a new reactivity of the Pd-catalyzed coupling of 2-amino-3-bromo-aromatic and heteroaromatic compounds with sulfonylhydrazones (Barluenga reaction).The new catalyst system and modulation of the electronic nature of hydrazone that were needed for successful reaction are described herein.
Photochemical Organocatalytic Benzylation of Allylic C–H Bonds
作者:Emilien Le Saux、Margherita Zanini、Paolo Melchiorre
DOI:10.1021/jacs.1c11712
日期:2022.1.26
We report a radical-based organocatalytic method for the direct benzylation of allylic C–H bonds. The process uses nonfunctionalized allylic substrates and readily available benzyl radical precursors and is driven by visible light. Crucial was the identification of a dithiophosphoric acid that performs two distinct catalytic roles, sequentially acting as a catalytic donor for the formation of photoactive
Branched Arylalkenes from Cinnamates: Selectivity Inversion in Heck Reactions by Carboxylates as Deciduous Directing Groups
作者:Jie Tang、Dagmar Hackenberger、Lukas J. Goossen
DOI:10.1002/anie.201605744
日期:2016.9.5
A decarboxylative Mizoroki–Heck coupling of aryl halides with cinnamic acids has been developed in which the carboxylate group directs the arylation into its β‐position before being tracelessly removed through protodecarboxylation. In the presence of a copper/palladium catalyst, both electron‐rich and electron‐deficient arylbromides and chlorides bearing numerous functionalities were successfully