Premium
A highly regioselective synthesis of δ‐lactones from meadowfoam fatty acids
Author(s) -
Isbell Terry A.,
Plattner Beth A.
Publication year - 1997
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-997-0161-6
Subject(s) - regioselectivity , chemistry , lactone , yield (engineering) , solvent , methylene , organic chemistry , catalysis , medicinal chemistry , sulfuric acid , chloride , materials science , metallurgy
Meadowfoam fatty acids, when treated with mineral acid catalysts in the presence of polar nonparticipating solvents, undergo a facile ring closure to form δ‐lactones. Perchloric and sulfuric acids catalyze the cyclization at concentrations of 0.6–13 mole equivalents, both neat and in the presence of solvent. Under constant acid concentrations, methylene chloride was found to increase the rate of reaction, the regioselectivity for the formation of δ‐lactone, and the overall yield. In the absence of solvent, increased acid concentration improved the yield of lactone but reduced regioselectivity for the δ‐isomer. Solvent polarity plays a significant role in the regioselectivity of the cyclization for δ‐lactone, with solvents of higher dielectric strength providing larger δ/γ ratios (38:1) and higher yields up to 92%.