Student Authors
Student Authors
Yidan Tang '19
Rowan Meador '16
Casina Malinchak '13
Emily Harrison '18
Kimberly McCaskey '20
Melanie Hempel '20
Document Type
Article
Publication Date
12-27-2019
Department 1
Chemistry
Abstract
Air-stable iron carbonyl compounds bearing cyclopentadienone ligands with varying substitution were explored as catalysts in dehydrogenative diol lactonization reactions using acetone as both the solvent and hydrogen acceptor. Two catalysts with trimethylsilyl groups in the 2- and 5-positions, [2,5-(SiMe3)2-3,4-(CH2)4(η4-C4C═O)]Fe(CO)3 (1) and [2,5-(SiMe3)2-3,4-(CH2)3(η4-C4C═O)]Fe(CO)3 (2), were found to be the most active, with 2 being the most selective in the lactonization of diols containing both primary and secondary alcohols. Lactones containing five-, six-, and seven-membered rings were successfully synthesized, and no over-oxidations to carboxylic acids were detected. The lactonization of unsymmetrical diols containing two primary alcohols occurred with catalyst 1, but selectivity was low based on alcohol electronics and modest based on alcohol sterics. Evidence for a transfer dehydrogenation mechanism was found, and insight into the origin of selectivity in the lactonization of 1°/2° diols was obtained. Additionally, spectroscopic evidence for a trimethylamine-ligated iron species formed in solution during the reaction was discovered.
Copyright Note
This is the author's version of the work. This publication appears in Gettysburg College's institutional repository by permission of the copyright owner for personal use, not for redistribution.
DOI
10.1021/acs.joc.9b01884
Version
Post-Print
Recommended Citation
Tang, Y.; Meador, R. I. L.; Malinchak, C. T.; Harrison, E. E.; McCaskey, K. A.; Hempel, M. C.; Funk, T. W. (Cyclopentadienone)iron-Catalyzed Transfer Dehydrogenation of Symmetrical and Unsymmetrical Diols to Lactones. J. Org. Chem. 2020, 85, 1823–1834.
Required Publisher's Statement
This article is available on the publisher's website.