Ligand Effects on Negishi Couplings of Alkenyl Halides
摘要:
Negishi couplings at olefinic centers do not always occur with the anticipated maintenance of stereochemistry. The source of erosion has been traced to the ligand, and a modified method has been developed that solves the stereochemical issue and significantly improves yields of Negishi couplings in general.
Intermolecular Pauson–Khand-Type Reaction of Vinyl Iodides with Alkynes and a CO Surrogate
作者:Philip Boehm、Elliott H. Denton、Joel Wick、Bill Morandi
DOI:10.1021/acs.joc.2c02465
日期:——
three-component reaction utilizes vinyl iodides and internal alkynes to form the carbon framework of the cyclopentenone with Cr(CO)6 serving as an easy to handle, solid CO surrogate, and a hydrosilane as a hydride source. We demonstrate the scope of the reaction which includes a wide range of functional groups. The reaction is regioselective, with the use of linear or branched vinyl iodides resulting in
Palladium-Catalyzed Carbene Insertion and Trapping with Carbon Nucleophiles
作者:Sean K. J. Devine、David L. Van Vranken
DOI:10.1021/ol800431w
日期:2008.5.1
Palladium catalysts are shown to catalyze the three-component coupling of vinyl halides, trimethylsilyldiazomethane, and stabilized carbon nucleophiles. The reaction is believed to proceed through a palladium-carbene intermediate LX(R)Pd=CHSiMe3 that undergoes migration of the vinyl substituent to the electrophilic carbene center to generate an eta(3)-allylpalladium intermediate. The allylpalladium intermediate is attacked by the carbon nucleophile to generate a vinylsilane product.