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.