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On the Necessity of One‐Pot Tautomer Trapping in Asymmetric Michael Reactions of Arylideneisoxazol‐5‐ones
Author(s) -
Macchia Antonio,
Cuomo Valentina Dafnae,
Di Mola Antonia,
Pierri Giovanni,
Tedesco Consiglia,
Palombi Laura,
Massa Antonio
Publication year - 2020
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202000286
Subject(s) - tautomer , michael reaction , chemistry , electrophile , adduct , knoevenagel condensation , yield (engineering) , organic chemistry , combinatorial chemistry , catalysis , materials science , metallurgy
Herein we report the first asymmetric Michael reaction of arylidene‐isoxazol‐5‐one with 1,3‐diesters. Despite complex tautomer equilibria of the obtained Michael adducts, the one‐pot entrapping strategy by the aid of different electrophiles/protecting groups led to the selective isolation of diverse N ‐substituted isoxazol‐5‐ones in very high overall yield and good enantioselectivity. Asymmetric three components Michael/electrophilic tautomer‐entrapping and four‐component Knoevenagel/Michael/electrophilic‐tautomer‐entrapping methodologies have also been developed. The enantiopurity of several final products was further increased after crystallization, up to > 99.9:0.1 er in good overall yields.