Asymmetric Synthesis of 3-Allyloxindoles and 3-Allenyloxindoles by Scandium(III)-Catalyzed Claisen Rearrangement Reactions
作者:Zeng-Wei Lai、Chuan Liu、Hongbin Sun、Shu-Li You
DOI:10.1002/cjoc.201700486
日期:2017.10
Scandium‐catalyzed asymmetric Claisenrearrangementreactions of 2‐allyloxyindoles and 2‐propargyloxyindoles provide a novel approach to diverse 3‐allyloxindoles and 3‐allenyloxindoles in excellent yields (up to 99%) and enantioselectivity (up to 99% ee) under mild reaction conditions. The scandium catalyst was derived from Sc(OTf)3 and Pybox ligand.
Copper(II)- and Palladium(II)-Catalyzed Enantioselective Claisen Rearrangement of Allyloxy- and Propargyloxy-Indoles to Quaternary Oxindoles and Spirocyclic Lactones
作者:Trung Cao、Elizabeth C. Linton、Joshua Deitch、Simon Berritt、Marisa C. Kozlowski
DOI:10.1021/jo302039n
日期:2012.12.21
In this Article, a strategy to obtain highly enantio-selective catalysts for the Claisen rearrangement of allyloxy- and propargyloxy-indoles is outlined. Ultimately, copper BOX and palladium BINAP or PHOX catalysts were discovered as superior in catalyzing Claisen rearrangements of allyloxy- or proparyloxy-substituted indoles to generate oxindoles bearing allyl- or allenyl-substituted quaternary centers. This method proved to be tolerant of a broad range of functional groups. Tandem reactions of the silyl-allene products provide rapid access to a variety of spirocyclic oxindoles in one operation.