Electrophilic Phosphonium Cations as Lewis Acid Catalysts in Diels–Alder Reactions and Nazarov Cyclizations
作者:Maria Vogler、Lars Süsse、James H. W. LaFortune、Douglas W. Stephan、Martin Oestreich
DOI:10.1021/acs.organomet.8b00496
日期:2018.10.8
[(C6F5)3PF]+[B(C6F5)4]− is shown to catalyze Diels–Alderreactions of challenging dienophile/enophile combinations and Nazarov cyclizations of various precursors. Several other electrophilic phosphonium cations (EPCs) have been tested for comparison. This systematic study demonstrates the power of these Lewis acids to act as catalysts for synthetically useful pericyclic reactions.
高亲电性的氟阳离子[(C 6 F 5)3 PF] + [B(C 6 F 5)4 ] -已显示出催化Diels-Alder反应的挑战,挑战了亲二烯体/亲烯体的组合以及各种前体的纳扎罗夫环化。已测试了其他几种亲电phospho阳离子(EPC)进行比较。这项系统的研究证明了这些路易斯酸作为合成上有用的周环反应的催化剂的能力。
Salen Promoted Enantioselective Nazarov Cyclizations of Activated and Unactivated Dienones
作者:Gerri E. Hutson、Yunus E. Türkmen、Viresh H. Rawal
DOI:10.1021/ja401908m
日期:2013.4.3
A novel class of chiral 5,5'-di(2,4,6-trialkyl)-aryl salen-metal complexes have been developed and shown to catalyze highly enantioselective Nazarov cyclization reactions, giving rise to cyclopentenoids in 90:10-98:2 er. Significantly, the catalysts also promote, for the first time, highly enantioselective Nazarov reactions of "unactivated" dienones, producing hydrindenone products having in place three contiguous chiral centers.