Calix[4]pyrrole (1), calix[2]m-benzo[4]pyrrole (2), 10α,20β- and 10α,20α- bis(4-nitrophenyl)-calix[4]pyrroles 3 and 4, respectively, were found to exhibit various organocatalytic activities in the diastereoselective vinylogous addition reaction of 2-trimethylsilyloxyfuran (TMSOF, 7) to aldehydes. The γ-hydroxybutenolide products are obtained in fairly good yields and with moderate diastereoselectivity. The structures of the catalysts, as well as the reaction conditions, strongly influence the efficiency of the reaction.
研究发现,在 2-三甲基
硅氧基
呋喃(TMSOF,7)与醛的非对映选择性
乙烯基加成反应中,
钙并[4]
吡咯(1)、
钙并[2]间苯并[4]
吡咯(2)、10α,20β- 和 10α,20α- 双(4-
硝基苯基)-
钙并[4]
吡咯 3 和 4 分别表现出不同的有机催化活性。γ-羟基
丁烯内酯产物的产率相当高,而且具有适度的非对映选择性。催化剂的结构和反应条件对反应的效率影响很大。