[2+2] Photocycloaddition of two olefins is a general method to assemble the core scaffold, cyclobutane, found in numerous bioactive molecules. A new approach to synthesize cyclobutanes through multicomponentcascade reactions by merging aldol reaction and Witting reaction with visible‐light‐induced [2+2] cycloaddition is reported. An array of cyclobutanes with high selectivity has been achieved from
Palladium(II)-catalyzed tandem annulation reaction of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins
作者:Huan Wang、Xiuling Han、Xiyan Lu
DOI:10.1016/j.tet.2013.07.057
日期:2013.10
A palladium(II)-catalyzed highly regioselective tandem reactions of o-alkynylbenzoates with methyl vinyl ketone for the synthesis of isocoumarins was developed. It is a convenient, mild and environmentally benign reaction with moderate to high yield. The reaction is initiated by the Pd(II) species and regenerate the Pd(II) species to complete the catalytic cycle without the necessity of a redox system
AbstractA catalytic reaction between terminal alkynes, acetylenic esters, and oxiranes has been described. This domino transformation serves as a useful sequential and one-pot method for the synthesis of 2H-pyran-4-carboxylate skeletons from the readily available starting materials. In situ-generated copper acetylides treated initially with oxiranes in the presence of copper catalysts and tetrabutylphosphonium
Here is the first visible light catalytic intermolecular cross [2 + 2] cycloaddition of enynes with alkenes to alkynyl cyclobutanes established with good functional group tolerance and high reaction efficiency and selectivity. Detailed studies reveal that enynes, including nonaromatic ones, can be sensitized by fac-Ir(ppy)3 via an energy transfer pathway. Addition of the Lewis acid PPh3AuNTf2 enables