Enantio- and Diastereoselective Double Mannich Reaction between Ketones and Imines Catalyzed by Zn-ProPhenol
作者:Barry M. Trost、Elumalai Gnanamani
DOI:10.1021/acs.orglett.0c00318
日期:2020.2.21
Herein we present a Zn-ProPhenol-catalyzed double Mannich reaction between ynones and imines that generates 1,3-diamines in excellent yield as well as diastereo- and enantioselectivity (>99.5% ee). With 2.2 equiv of a single imine electrophile, we obtain pseudo-symmetrical diamines whereas, with two different imine partners, we obtain unsymmetrically substituted 1,3-diamines with three contiguous stereocenters
Phosphine-catalysed denitrative rearomatising (3 + 2) annulation of α,β-ynones and 3-nitroindoles
作者:Lona Dutta、Anwita Chattopadhyay、Nisha Yadav、S. S. V. Ramasastry
DOI:10.1039/d2ob02180c
日期:——
We describe a metal-free strategy to access various α-arylidene cyclopenta[b]indoles via phosphine-catalysed (3 + 2) annulation of α,β-ynones and 3-nitroindoles. For the first time, the rearomatisation of the indole nucleus was observed in such an annulative transformation. The method was extended to the synthesis of an antimalarial natural product, bruceolline E.
Alkynylketones were obtained in good yield from reaction of 3-(N-isopropylamino)-1-arylbut-2-en-1-ones with chlorotrimethylsilane. On the other hand, t-butyldimethylchlorosilane leads to gamma-silylated enaminones. Compounds arising from silicon attack at the oxygen atom are never observed. Evidences of the mechanistic pathway of the reaction are reported.
NHC-catalyzed regiodivergent transformations of Ynones with trifluoromethyl ketones: Aldol reaction or [3+2] annulation
作者:Fangfang Lu、Bai Shi、Wei Cao、Huiping Yin、Tianjiao Huang、Kai Zhang、Changsheng Yao