Mild, Rapid, and Inexpensive Microwave-Assisted Synthesis of Allylic and Propargylic Esters

Abstract

A variety of allylic and propargylic esters were rapidly prepared via microwave heating of their corresponding mixed anhydride derived from pivaloyl chloride. The reaction conditions were modified to account for the sterics of the alcohol and the electronics of the carboxylic acid.

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GRAPHICAL ABSTRACT

Keywords:

• Allylic esters
• esterification
• microwave-assisted synthesis
• mixed anhydride
• propargylic esters

ACKNOWLEDGMENTS

This research has been supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canada Foundation for Innovation, the Ontario Research Fund, and Carleton University.

Notes

^a Catalyst loading was 50 mol% for Ti(O-i-Pr)₄ and 10 mol% for B(OH)₃.

^b Ratios determined by integration of ¹H NMR spectra of crude reaction mixtures.

^a 2-Chloropyridine was used in place of pyridine.

^a Reaction conducted using 2.0 g (6.6 mmol) of 8.

^b The modest yield is ascribed to the volatility of 25.