Divergent Outcomes of Carbene Transfer Reactions from Dirhodium- and Copper-Based Catalysts Separately or in Combination
作者:Xinfang Xu、Wen-Hao Hu、Peter Y. Zavalij、Michael P. Doyle
DOI:10.1002/anie.201105557
日期:2011.11.18
Divergent catalysis: The use of copper and rhodium catalysts separately or in combination directs reactions betweenvinyldiazoacetates 1 and cinnamaldehydes 2 from formal [4+3] cycloaddition (epoxidation followed by Cope rearrangement), to intramolecular cyclopropanation, to Mukaiyama‐aldol reactions. The reactions proceed selectively and in high yield.
Role of Donor–Acceptor Cyclopropenes in Metal Carbene Reactions. Conversion of <i>E</i>-Substituted Enoldiazoacetates to <i>Z</i>-Substituted Metallo-Enolcarbenes
作者:Kuiyong Dong、Kostiantyn O. Marichev、Michael P. Doyle
DOI:10.1021/acs.organomet.9b00427
日期:2019.10.28
vinylcarbene cycloaddition reactions. These reactions often occur with the intervention of donor–acceptor (D-A) cyclopropenes that can serve as metal carbene sources. Pathways to cycloaddition products that occur with and without D-A cyclopropene involvement have been identified. E-γ-Substituted enoldiazoacetates do not undergo cycloaddition reactions unless they first form D-A cyclopropene intermediates. When
Catalytic Asymmetric Syntheses of Quinolizidines by Dirhodium-Catalyzed Dearomatization of Isoquinolinium/Pyridinium Methylides–The Role of Catalyst and Carbene Source
作者:Xichen Xu、Peter Y. Zavalij、Michael P. Doyle
DOI:10.1021/ja406482q
日期:2013.8.21
enantioenriched substituted quinolizidines has been achieved by chiraldirhodium(II) carboxylate-catalyzed dearomatizing formal [3 + 3]-cycloaddition of isoquinolinium/pyridinium methylides and enol diazoacetates. Coordination of Lewis basic methylides to dirhodium(II) prompts the rearrangement of the enol-carbene that is bound to dirhodium to produce a donor-acceptor cyclopropene. The donor-acceptor
Synthesis of Tetrahydropyridazines by a Metal-Carbene-Directed Enantioselective Vinylogous NH Insertion/Lewis Acid-Catalyzed Diastereoselective Mannich Addition
作者:Xinfang Xu、Peter Y. Zavalij、Michael P. Doyle
DOI:10.1002/anie.201203962
日期:2012.9.24
A versatile cascade of reactions, triggered by RhII‐catalyzed diazo decomposition followed by a vinylogous NH insertion/Lewisacidcatalyzed Mannich addition, that produces highly substituted 1,2,3,6‐tetrahydropyridazines in up to 97 % ee with high yield and diastereocontrol has been developed.
Enantioselective Catalytic Cyclopropanation–Rearrangement Approach to Chiral Spiroketals
作者:Kuioyng Dong、Raj Gurung、Xinfang Xu、Michael P. Doyle
DOI:10.1021/acs.orglett.1c01113
日期:2021.5.21
A highly enantioselective synthesis of chiral heterobicyclic spiroketals is reported via a “one-pot” cyclopropanation–rearrangement (CP-RA) cascade reaction that is sequentially catalyzed by a chiral Rh(II) catalyst and tetrabutylammonium fluoride (TBAF). Exocyclic vinyl substrates form spirocyclopropanes with tert-butyldimethylsilyl-protected enoldiazoacetates in excellent yields and with excellent