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Merging Brønsted Acid and Hydrogen‐Bonding Catalysis: Metal‐Free Dearomatization of Phenols via ipso ‐Friedel‐Crafts Alkylation to Produce Functionalized Spirolactams
Author(s) -
Harada Shingo,
Kwok Irene MeiYi,
Nakayama Hiroki,
Kanda Ayaka,
Nemoto Tetsuhiro
Publication year - 2018
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201701287
Subject(s) - chemistry , friedel–crafts reaction , chemoselectivity , catalysis , brønsted–lowry acid–base theory , intramolecular force , carbenoid , alkylation , phenols , organic chemistry , combinatorial chemistry , hydrogen bond , organocatalysis , transition metal , rhodium , enantioselective synthesis , molecule
Intramolecular dearomative cyclization of phenols with α‐diazoamide units for synthesizing functionalized spirolactams was developed by merging Brønsted acid and hydrogen‐bonding catalysis as an advantageous alternative to transition metal catalysis. This metal carbenoid‐free strategy enables high chemoselectivity by suppressing potentially competing C−H insertion reactions and a Büchner reaction. Preliminary mechanistic studies were performed to elucidate the positive effect of the combined use of the catalysts, and extension to an asymmetric reaction was achieved.