Recyclable tetraarylphosphonium supported chiral imidazolidin-4-one organocatalyst for Diels–Alder reactions
摘要:
The tetraarylphosphonium supported chiral imidazolidin-4-ones were synthesized and used to catalyze the Diels-Alder reactions of cyclopentadiene and alpha,beta-unsaturated aldehydes. High enantiomeric excesses and good yields were obtained, and catalyst recycling (up to five cycles) was accompanied by almost intact enantioselectivity and some loss of the chemical efficiency. (C) 2013 Elsevier B.V. All rights reserved.