Highly Enantioselective Nickel-Catalyzed Hydrocyanation of Disubstituted Methylenecyclopropanes Enabled by TADDOL-based Diphosphite Ligands
作者:Rongrong Yu、Xianjie Fang
DOI:10.1021/acs.orglett.9b04374
日期:2020.1.17
A vast range of novel TADDOL-based diphosphite ligands were first synthesized and applied in the nickel-catalyzed asymmetric hydrocyanation of disubstituted methylenecyclopropanes. By employing these new catalysts, the conversion of diverse methylenecyclopropanes into their corresponding allylic nitriles was first enabled, in good yield with excellent enantioselectivities.
Palladium-catalyzed hydroalkylation of methylenecyclopropanes with simple hydrazones
作者:Jinzhong Yao、Zhangpei Chen、Lin Yu、Leiyang Lv、Dawei Cao、Chao-Jun Li
DOI:10.1039/d0sc01221a
日期:——
A palladium-catalyzed hydroalkylation reaction of methylenecyclopropanes via highly selective C–C σ-bond scission was achieved under mild conditions, in which simple hydrazones served as carbanion equivalents. This method featured good functional group compatibility, affording high yields of C-alkylated terminal alkenes.
Metal-Free Ring Expansions of Methylenecyclopropanes Through Nitrene Equivalent
作者:Di-Han Zhang、Yin Wei、Min Shi
DOI:10.1002/ejoc.201100629
日期:2011.7.19
An interesting nitrene equivalent mediated metal-free ring expansion of methylenecyclopropanes was developed in the presence of iodosobenzenediacetate (PIDA) and 3-amino-2-ethyl-4(3H)-quinazolinone under mild conditions. A variety of cyclobutylidene hydrazine derivatives were obtained in moderate to excellent yields as separable (Z)/(E) isomeric mixtures.
Spiropentanes undergo carbonylation under an atmosphere of carbon monoxide in the presence of a rhodium(I)−phosphine catalyst, giving 3-methylcyclopent-2-enones. The catalytic cycle involves two mechanistically different carbon−carbon cleavage processes. The spiropentane carbonylation was successfully applied to a short synthesis of (±)-β-cuparenone.
Enantioselective Synthesis of γ-Aryl-γ-butyrolactones by Sequential Asymmetric Epoxidation, Ring Expansion, and Baeyer−Villiger Oxidation
作者:Bin Wang、Yu-Mei Shen、Yian Shi
DOI:10.1021/jo061341j
日期:2006.12.1
N-tolyl-substituted oxazolidinone-containing ketone as catalyst and Oxone as oxidant via a sequential asymmetric epoxidation of benzylidenecyclopropanes, ring expansion, and Baeyer−Villigeroxidation. Up to 91% ee was obtained. Optically active cyclobutanones can also be obtained by suppressing the Baeyer−Villigeroxidation with use of more ketone catalyst and less Oxone.