Secondary phosphine oxides O=PHR2 (SPOs) were identified as multitalented preligands for the chemoselective Pd‐catalyzedoxidation of alcohols by a hydrogen‐abstracting methodology. SPOs were found to promote the hydrogen‐abstraction step as well as hydrogen transfer to a Michael acceptor by generating a putative active H−Pd species. The catalytic system operates under neutral conditions and was proven
Chiral cycloalkylidene α,β-unsaturated iminium approach to stereoselective formal [3+3] cycloaddition reaction in spiroheterocycle synthesis
作者:Michael J McLaughlin、Hong C Shen、Richard P Hsung
DOI:10.1016/s0040-4039(00)02018-9
日期:2001.1
An approach to stereoselective formal [3+3] cycloadditionreaction using chiral cycloalkylidene α,β-unsaturated iminiums is described here leading to preparations of spiroheterocycles in modest stereoselectivity. The reversibility of 6π-electron electrocyclic ring closure did not always lead to the thermodynamically more favored product. These observations led to other useful mechanistic understanding