Copper(II)- and Palladium(II)-Catalyzed Enantioselective Claisen Rearrangement of Allyloxy- and Propargyloxy-Indoles to Quaternary Oxindoles and Spirocyclic Lactones

In this Article, a strategy to obtain highly enantioselective
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.

本文报道了一种可制备适用于烯丙氧基吲哚与炔丙氧基吲哚克莱森重排（Claisen rearrangement）反应的高对映选择性催化剂的策略。研究最终发现，铜-BOX、钯-BINAP与钯-PHOX催化剂在催化烯丙氧基或炔丙氧基取代吲哚的克莱森重排反应中性能更优，可生成带有烯丙基或联烯基取代季碳中心的羟吲哚（oxindoles）。该方法对多种官能团均具有良好的兼容性。硅基联烯产物的串联反应可通过一锅法快速构建多种螺环羟吲哚类化合物。