Stereoselective Rh<sub>2</sub>(<i>S</i>-IBAZ)<sub>4</sub>-Catalyzed Cyclopropanation of Alkenes, Alkynes, and Allenes: Asymmetric Synthesis of Diacceptor Cyclopropylphosphonates and Alkylidenecyclopropanes
作者:Vincent N. G. Lindsay、Dominic Fiset、Philipp J. Gritsch、Soula Azzi、André B. Charette
DOI:10.1021/ja3099728
日期:2013.1.30
A mild and highly stereoselective rhodium(II)-catalyzed cyclopropanation of alkenes, alkynes, and allenes with diacceptor diazo compounds is reported. Using the phosphonate moiety as an efficient trans-directing group, the first catalytic asymmetric route to diacceptor cycloprop(en)ylphosphonates was developed by employing an α-cyano diazophosphonate and Rh(2)(S-IBAZ)(4) as chiral catalyst. The isosteric
报道了一种温和且高度立体选择性的铑 (II) 催化的烯烃、炔烃和丙二烯与二受体重氮化合物的环丙烷化反应。使用膦酸酯部分作为有效的反式导向基团,通过使用 α-氰基重氮膦酸酯和 Rh(2)(S-IBAZ)(4) 作为手性催化剂,开发了第一个催化不对称二受体环丙(烯)基膦酸酯的路线。膦酸和羧酸衍生物的等排特性允许在该过程中替代使用 α-氰基重氮酯,从而以高产率和立体选择性生成 α-氰基环丙(烯)基羧酸酯。利用该系统中涉及的氰基卡宾中间体的特殊反应性,相容底物的范围可以扩展到取代的丙二烯,
Rhodium-Catalyzed Cyclopropanation of Fluorinated Olefins: A Straightforward Route to Highly Functionalized Fluorocyclopropanes
作者:Amandine Pons、Hélène Beucher、Pavel Ivashkin、Gérald Lemonnier、Thomas Poisson、André B. Charette、Philippe Jubault、Xavier Pannecoucke
DOI:10.1021/acs.orglett.5b00576
日期:2015.4.3
An efficient access to highlyfunctionalized monofluorocyclopropanes is described. The developed methodology allowed straightforward access to a large panel of polysubstituted fluorinated cyclopropanes in good to excellent yields and good diastereoselectivities. The Rh-catalyzed cyclopropanation proved to be efficient on several fluorinated olefins and several diazo compounds. This method represents
Enantioselective Cyclopropenation of Alkynes with Acceptor/Acceptor-Substituted Diazo Reagents via Co(II)-Based Metalloradical Catalysis
作者:Xin Cui、Xue Xu、Hongjian Lu、Shifa Zhu、Lukasz Wojtas、X. Peter Zhang*
DOI:10.1021/ja111334j
日期:2011.3.16
The cobalt(II) complex of a new D(2)-symmetric chiral porphyrin 3,5-diMes-ChenPhyrin, [Co(P2)], has been shown to be a highly effective chiral metalloradical catalyst for enantioselective cyclopropenation of alkynes with acceptor/acceptor-substituted diazo reagents, such as α-cyanodiazoacetamides and α-cyanodiazoacetates. The [Co(P2)]-mediated metalloradical cyclopropenation is suitable to a wide range
The cobalt(II) complex of new D2-symmetric chiral porphyrin 3,5-DiMes-ChenPhyrin, [Co(P2)], has been shown to be a highly effective chiral metalloradical catalyst for enantioselective cyclopropenation of alkynes with acceptor/acceptor-substituted diazo reagents such as α-cyanodiazoacetamides and α-cyanodiazoacetates. The [Co(P2)]-mediated metalloradical cyclopropenation is suitable to a wide range of terminal aromatic and related conjugated alkynes with varied steric and electronic properties, providing the corresponding tri-substituted cyclopropenes in high yields with excellent enantiocontrol of the all-carbon quaternary stereogenic centers. In addition to mild reaction conditions, the Co(II)-based metalloradical catalysis for cyclopropenation features a high degree of functional group tolerance.
A ‘sulfonyl-azide-free’ (SAFE) aqueous-phase diazo transfer reaction for parallel and diversity-oriented synthesis
作者:Dmitry Dar’in、Grigory Kantin、Mikhail Krasavin
DOI:10.1039/c9cc02042j
日期:——
Diazotransferreactions are notoriously associated with the use of potentially explosive sulfonyl azides. The first ‘sulfonyl-azide-free’ (SAFE) protocol for producing diazo compounds from their active-methylene precursors via the Regitz diazotransferreaction was developed and has displayed a remarkable substrate scope. It can be applied to generating arrays of diazo compounds for further evolution