2071-44-5Relevant articles and documents
Highly regio- and diastereoselective chromium(0)-catalysed cyclopropanation of 1-alkoxy-1,3-dienes with diazo compounds
Hahn, Norbert D.,Nieger, Martin,Doetz, Karl Heinz
, p. 1049 - 1056 (2004)
Pentacarbonyl(η2-cis-cyclooctene)chromium(0) (1) is an efficient catalyst for diazo decomposition and selective [2+1]-cycloaddition reactions of the resulting carbene intermediates with electron-rich dienes. The cyclopropanation of 1-alkoxy-1,3
(PNP)Cobalt-Catalyzed Olefination of Diazoalkanes
Chirik, Paul J.,Semproni, Scott P.,Yruegas, Sam
supporting information, (2022/03/17)
Addition of excess diazoalkane to the pincer-supported cobalt(I) dinitrogen complex (tBumPNP)CoN2 (tBumPNP = modified 2,6-bis[(ditert-butylphosphino)methyl]pyridine) resulted in the catalytic formation of the homocoupled alkene product with concomitant loss of N2. Monosubstituted diazoalkanes, trimethylsilyldiazomethane and tolyldiazomethane, generated the olefin product in quantitative yield with exclusive (E)-stereoselectivity. Disubstituted diazoalkanes, diphenyldiazomethane and 9-diazofluorene, also yielded the olefin as the major product along with minor azine coupling. Investigations into the nature of the diazoalkane-cobalt interaction by multinuclear NMR spectroscopy and X-ray diffraction established end-on diazoalkane cobalt complexes as the resting states. The isolated four-coordinate cobalt diazoalkane complexes promoted conversion to the corresponding olefin. The reaction of (tBumPNP)CoN2 with an α-diazo-β-ketoester resulted in the formation of a five-coordinate Co(I)-diazoalkane complex with a chelating ester unit that was unreactive for olefination.
Substituent Effects on Reactions of [RhCl(COD)]2 with Diazoalkanes
Cui, Mingxu,Lin, Shujuan,Sung, Herman H. Y.,Williams, Ian D.,Lin, Zhenyang,Jia, Guochen
, p. 905 - 915 (2019/03/04)
The reactions of [RhCl(COD)]2 with a series of diazoalkanes with different substitutents were investigated. The outcomes of the reactions were found to be substituent-dependent via four different pathways. (1) The reactions with diazoindenes produced ??5-cyclopentadienyl complexes. (2) The reaction with diazofluorene produced a mixture of olefin and azine compounds. (3) The reactions with monosubstituted diazoalkanes RCHN2 (R = Ph, MeO2C) produced olefins RCHa?CHR. (4) The reaction with the disubstituted diazoalkane Ph2CN2 produced the azine Ph2Ca?N-Na?CPh2 only. Computational studies have been carried out to understand the interesting substituent effect by comparing the kinetics and thermodynamics of the reaction pathways. It was found that the reactions with diazocyclopentadiene, diazoindene, and Ph2CN2 are kinetically controlled, while the reactions with RCHN2 and diazofluorene are both thermodynamically and kinetically controlled.
Cyclopropanespiro-β-lactones derived from 4-[(Z)-ethylidene]-3- methyloxetan-2-one: Diastereoselective formation and rearrangement reactions
Geraghty, Niall W.A.,McArdle, Patrick,Mullen, Laverne M.A.
experimental part, p. 3546 - 3552 (2011/06/11)
The metal catalysed reaction of monosubstituted diazo esters and ketones with 4-[(Z)-ethylidene]-3-methyloxetan-2-one results in the formation of cyclopropanespiro-β-lactones. In contrast to most alkene cyclopropanations, including those involving diketene, the reaction occurs diastereoselectively. A computational model of the reaction has been developed that accounts for the observed stereochemistry. The metal promoted thermal rearrangement of these spiro compounds is also unusual in that it affords pyranones, rather than the decarboxylation products characteristic of β-lactones in general, or the furanones formed from diketene derived cyclopropanespiro-β-lactones.
