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Generation of an 4‐Isoxazolyl Anion Species: Facile Access to Multifunctionalized Isoxazoles
Author(s) -
Morita Taiki,
Fuse Shinichiro,
Nakamura Hiroyuki
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201608039
Subject(s) - isoxazole , chemistry , halogenation , substituent , reagent , combinatorial chemistry , electrophile , synthon , organic chemistry , catalysis
Abstract A direct functionalization of unsubstituted isoxazole ( 1 ) was achieved by generation of 4‐isoxazolyl anion species ( 3 ). An efficient 4‐iodination of isoxazole and halogen–metal exchange reaction using a turbo Grignard reagent ( i PrMgCl⋅ LiCl) were essential for the generation of 3 , which reacted with various electrophiles to give 4‐functionalized isoxazoles in good to high yields. Isoxazolyl boronate, boronic acid, and stannane were also synthesized as useful building blocks from 1 . The current methods enabled us to synthesize multi‐functionalized isoxazoles by introducing each substituent into the desired positions. Furthermore, total synthesis of triumferol, which was isolated from Triumfetta rhomboidea, was achieved from 1 in only three steps.