Premium
Michael Addition versus 1,3‐Cycloaddition Reactions of Pyridinium Ylides with (Arylmethylene)isoxazol‐5‐ones: Diastereoselective Formation of 4‐[1‐Aryl‐2‐(1‐pyridinio)ethyl]isoxazolium‐5‐olates
Author(s) -
Risitano Francesco,
Grassi Giovanni,
Bruno Giuseppe,
Nicolò Francesco
Publication year - 1997
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199719970224
Subject(s) - chemistry , pyridinium , aryl , cycloaddition , michael reaction , proton nmr , medicinal chemistry , organic chemistry , catalysis , alkyl
The reactions of (arylmethylene)isoxazol‐5‐ones 1 with pyridinium ylides 2 lead to the diastereoselective formation of olates 4 . The reasons for the favored Michael addition and the unsuccessful subsequent cyclization to fused O‐heterocycles are discussed on the basis of X‐ray analysis as well as 1 H‐NMR and chemical evidences.