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Benzofulvenes in Trienamine Catalysis: Stereoselective Spiroindene Synthesis
Author(s) -
Donslund Bjarke S.,
Nielsen Rune Pagh,
Mønsted Sofie M. N.,
Jørgensen Karl Anker
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201605079
Subject(s) - stereocenter , stereoselectivity , cycloaddition , chemistry , intramolecular force , catalysis , organocatalysis , silyl ether , combinatorial chemistry , enantioselective synthesis , stereochemistry , organic chemistry , silylation
The asymmetric formation of spiroindenes containing up to four contiguous stereocenters from the reaction of benzofulvenes with 2,4‐dienals through trienamine catalysis is described. The benzofulvene core was found to be an excellent starting point for the synthesis of interesting spiroindenes through a formal cycloaddition pathway. The reaction was mediated by a diphenylprolinol silyl ether catalyst, and a diverse array of spiroindenes were obtained in high yields with excellent stereoselectivity. An attractive feature of the developed system is the possibility to diversify the product scaffold significantly by further manipulation of the chiral spiroindenes. Thus, three intramolecular ring‐closing reactions following the organocatalytic step resulted in highly complex polycyclic systems.