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Transition‐Metal‐Free Multicomponent Approach to Stereoenriched Cyclopentyl‐isoxazoles through C−C Bond Cleavage
Author(s) -
Subramanian Parthasarathi,
Kaliappan Krishna P.
Publication year - 2018
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201800608
Subject(s) - chemistry , oxime , nitrile , regioselectivity , cycloaddition , bond cleavage , alkyne , medicinal chemistry , catalysis , ketone , isoxazole , steric effects , combinatorial chemistry , organic chemistry
An efficient multicomponent reaction for the synthesis of stereoenriched cyclopentyl‐isoxazoles from camphor‐derived α‐oximes, alkynes, and MeOH is reported. Our method involved a series of cascade transformations, including the in situ generation of an I III catalyst, which catalyzed the addition of MeOH to a sterically hindered ketone. Oxidation of the oxime, and rearrangement of the α‐hydroxyiminium ion generated a nitrile oxide in situ, which, upon [3+2] cycloaddition reaction with an alkyne, delivered the regioselective product. This reaction was very selective for the syn ‐oxime. This multicomponent approach was also extended to the synthesis of a new glycoconjugate, camphoric ester‐isoxazole C ‐galactoside.