Metalloradical Activation of In Situ-Generated α-Alkynyldiazomethanes for Asymmetric Radical Cyclopropanation of Alkenes.
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DOI: 10.1021/jacs.1c13154
Abstract: α-Alkynyldiazomethanes, generated in situ from the corresponding sulfonyl hydrazones in the presence of a base, can serve as effective metalloradicophiles in Co(II)-based metalloradical catalysis (MRC) for asymmetric cyclopropanation of alkenes. With D2-symmetric chiral amidoporphyrin 2,6-DiMeO-QingPhyrin… read more here.
Keywords: cyclopropanation alkenes; situ generated; metalloradical activation; cyclopropanation ... See more keywords
Chromium-catalyzed cyclopropanation of alkenes with bromoform in the presence of 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine†
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DOI: 10.1039/d0sc00964d
Abstract: Chromium-catalyzed cyclopropanation of alkenes with bromoform was achieved to produce the corresponding bromocyclopropanes. In this catalytic cyclopropanation, an organosilicon reductant, 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-dihydropyrazine (1a), was indispensable for reducing CrCl3(thf)3 to CrCl2(thf)3, as well as for in situ… read more here.
Keywords: cyclopropanation; chromium catalyzed; cyclopropanation alkenes; alkenes bromoform ... See more keywords
Silver-catalyzed cyclopropanation of alkenes with alkynyl N-nosylhydrazones leading to alkynyl cyclopropanes.
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DOI: 10.1039/d2cc00099g
Abstract: Here, a novel method for the stereoselective synthesis of alkynyl cyclopropanes, by the silver-catalyzed alkynylcyclopropanation of alkenes using alkynyl N-nosylhydrazones as alkynyl carbene precursors, is reported. This method provides a straightforward and powerful approach for… read more here.
Keywords: cyclopropanation alkenes; catalyzed cyclopropanation; cyclopropanes silver; silver catalyzed ... See more keywords