In situ prepared Cp2ZrCl⊕ catalyzes the formation of dioxolenium ions from α,β-unsaturated epoxy esters. As a consequence of this activation process, acrylate, methacrylate and crotonate derivatives undergo a rapid and stereoselective cationic [4+2] cycloaddition with a wide range of dienes. Ring-extended carboxylic acid derivatives are formed in 1–7 h at 0–21 °C and in 50–90% yield after saponification
Highly diastereoselective diels-alder reaction mediated by a chiral auxiliary derived from amino indanol: The role of conformation on diastereoselectivity
作者:Ian W. Davies、Chris H. Senanayake、Laurie Castonguay、Robert D. Larsen、Thomas R. Verhoeven、Paul J. Reider
DOI:10.1016/0040-4039(95)01584-5
日期:1995.10
The oxazolidinone 2 derived from amino indanol 1 functions as a very efficient chiral auxiliary for the Diels-Alder reaction. The effect of conformation has been explored using a range of constrained phenyl glycinol analogues.
Asymmetric Diels-Alder cycloaddition reactions with chiral .alpha.,.beta.-unsaturated N-acyloxazolidinones