Pd(II)-Catalyzed Tandem Heterocyclization of 1-(1-Alkynyl)cyclopropyl Oxime Derivatives for the Synthesis of Functionalized Pyrroles
作者:Dong Pan、Yin Wei、Min Shi
DOI:10.1021/acs.orglett.6b02068
日期:2016.8.5
An efficient approach for the synthesis of highly functionalized pyrroles has been developed by a Pd(TFA)2-catalyzed tandem heterocyclization of 1-(1-alkynyl)cyclopropyl oxime derivatives under mild conditions. The reaction first proceeded via an intramolecular nucleophilic attack followed by a ring-opening process and then intermolecular nucleophilic attack as well as protonation to afford the desired
Metal-Free Synthesis of Homopropargylic Alcohols from Aldehydes
作者:Bruno V. M. Teodoro、Luiz F. Silva
DOI:10.1021/acs.joc.7b01629
日期:2017.11.17
This transformation is based on a one-pot procedure involving sequential α-alkynylation of acyclic aldehydes using hypervalent iodine reagents and borohydride reduction. The chemistry exhibits broad substrate scope and good scalability, providing a convenient route for the α-alkynylation of aldehydes along with the formation of a quaternary carbon center. The applicability of the method is demonstrated
Gold-Catalyzed Hydrative Carbocyclization of 1,5- and 1,7-Allenynes Mediated by π-Allene Complex: Mechanistic Evidence Supported by the Chirality Transfer of Allenyne Substrates
作者:Chun-Yao Yang、Guan-You Lin、Hsin-Yi Liao、Swarup Datta、Rai-Shung Liu
DOI:10.1021/jo8004777
日期:2008.7.1
We report PPh3AuCl/AgOTf-catalyzed hydrative carbocyclization of 1,5- and 1,7-allenynes to give cyclized ketones chemoselectively. In this transformation, hydration occurrs regioselectively at the C CPh carbon, accompanied by addition of the C CPh carbon to the two terminal allenyl carbons. This method is effective for the construction of a quaternary carbon center. On the basis of the chirality transfer of allenyne substrates, control experiments, and theoretic calculations, we propose that this hydrative carbocyclization proceeds through an initial pi-allene complex with a small energy barrier.