A novel catalytic system using I-2 and PhSiH3 for the intramolecular hydroalkoxylation of unactivated alkenes is described. NMR study indicated that in situ generated PhSiH2I is a possible active catalytic species. This catalytic system allows an efficient intramolecular hydroalkoxylation of phenyl-, trialkyl-, and 1,1-dialkyl-substituted alkenes as well as a variety of unactivated monoalkyl- and 1,2-dialkyl-substituted alkenes at room temperature. Mechanistic consideration based on significant experimental observations is also discussed.
Non-superimposable mirror image crystals of enantiomers by spontaneous resolution and the chiral discrimination mechanism
Non-superimposable mirror image crystals of both enantiomers (S/R) of cyclic gamma-alkenyl alcohol (2) have been recognized and remarkably identified by the naked eye. More interestingly, both crystals are an outcome of most astonishingly H-bond and intermolecular sigma/pi-pi interactions. They accounted for the relatively rare and less predictable spontaneous resolution with optical purity >99% ee from the racemic mixture. The chiral discrimination mechanism of this spontaneous resolution has also been proposed. (c) 2013 Fu-Xue Chen. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.