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Expedient Synthesis of 4‐Dialkylamino‐5 H ‐furan‐2‐ones by One‐Pot Sequential Pd‐Catalyzed Oxidative Carbonylation of 2‐Yn‐1‐ols–Conjugate Addition‐Lactonization
Author(s) -
Gabriele Bartolo,
Salerno Giuseppe,
Plastina Pierluigi,
Costa Mirco,
Crispini Alessandra
Publication year - 2004
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.200303151
Subject(s) - chemistry , furan , intramolecular force , catalysis , carbonylation , carbon monoxide , amide , medicinal chemistry , conjugate , oxidative phosphorylation , triple bond , stereochemistry , organic chemistry , double bond , mathematical analysis , biochemistry , mathematics
A novel synthesis of 4‐dialkylamino‐5 H ‐furan‐2‐ones 3 starting from very simple building blocks, i.e., α‐substituted 2‐yn‐1‐ols 1 , carbon monoxide, dialkylamines 2 and oxygen is reported. Reactions are carried out in 1,2‐dimethoxyethane at 100 °C and under 20 atm (at 25 °C) of a 4/1 mixture of CO/air in the presence of catalytic amounts of PdI 2 in conjunction with 10 equiv. of KI. Formation of 3 occurs through an ordered sequence of steps, namely (a) Pd‐catalyzed oxidative monoaminocarbonylation of 1 to give 4‐hydroxy‐2‐ynamides 4 , which can be isolated under appropriate conditions; (b) stereoselective conjugate addition of 2 to the triple bond of 4 , with formation of (not isolated) ( E )‐3‐dialkylamino‐4‐hydroxy‐2‐enamides; (c) intramolecular alcoholysis of the amide function of the latter to give the final product 3 .