DNA-Compatible [3 + 2] Nitrone–Olefin Cycloaddition Suitable for DEL Syntheses
作者:Christopher J. Gerry、Zhenhua Yang、Michele Stasi、Stuart L. Schreiber
DOI:10.1021/acs.orglett.9b00017
日期:2019.3.1
DNA-compatible chemistry restricts the types of chemical features that can be incorporated into DNA-encoded libraries (DELs). Here, a method to synthesize DNA-conjugated polycyclic isoxazolidines via a [3 + 2] nitrone-olefin cycloaddition is described. The reaction is compatible with many olefin-containing substrates and diverse N-alkylhydroxylamines. The ability to perform subsequent DNA ligation and
A new rhodium-catalyzedasymmetricarylativecyclization of nitrogen-tethered alkyne-enoate with arylboronic acids is described. In this process two new carbon–carbon bonds and one stereocenter are formed, providing access to pyrrolidines and piperidines with good enantioselectivities by to the use of C1-symmetric chiral monosubstituted diene ligands.
P<sup>III</sup>-Mediated intramolecular cyclopropanation and metal-free synthesis of cyclopropane-fused heterocycles
作者:Jiayong Zhang、Jiahang Hao、Zhiqiang Huang、Jie Han、Zhengjie He
DOI:10.1039/d0cc04086j
日期:——
A P(NMe2)3-mediated reductive intramolecular cyclopropanation is developed for the first time, which provides facileaccess to a wide variety of cyclopropane-fused heterocycles including chromanes, tetrahydroquinolines, lactones, and lactams. Catalytic hydrogenative ring-expansion of the cyclopropane-fused heterocycles is also elaborated, leading to various structurally important medium-sized heterocycles
Intramolecular photochemical [2 + 1]-cycloadditions of nucleophilic siloxy carbenes
作者:Amanda Bunyamin、Carol Hua、Anastasios Polyzos、Daniel L. Priebbenow
DOI:10.1039/d2sc00203e
日期:——
singlet nucleophiliccarbenes undergo rapid [2 + 1]-cycloaddition with tethered olefins to afford unique bicyclo[3.1.0]hexane and bicyclo[4.1.0]heptane scaffolds. This cyclopropanation process requires only visible light irradiation to proceed, circumventing the use of exogenous (photo)catalysts, sensitisers or additives and showcases a vastly underexplored mode of reactivity for nucleophilic carbenes
Enantioselective Desymmetrization of Prochiral Cyclohexanones by Organocatalytic Intramolecular Michael Additions to α,β-Unsaturated Esters
作者:Adam D. Gammack Yamagata、Swarup Datta、Kelvin E. Jackson、Linus Stegbauer、Robert S. Paton、Darren J. Dixon
DOI:10.1002/anie.201411924
日期:2015.4.13
cyclohexanediamine‐derived primary amine organocatalyst, a range of prochiral cyclohexanone derivatives possessing an α,β‐unsaturated ester moiety linked to the 4‐position afforded the bicyclic products, which possess three stereogenic centers, as single diastereoisomers in high enantioselectivity (83–99 % ee) and in good yields (60–90 %). Calculations revealed that stepwise CC bond formation and proton transfer