Preference for 6-Exo-Trigonal closures of ω-hydroxy-αβ-unsaturated esters
Abstract
Methyl 5-hydroxy-2-methylenevalerate (3) under basic conditions cyclises preferentially to α-methylene-δ-valerolactone (4) by a 6-Exo-Trig process which is a faster reaction than the alternative 6-Endo-Trig mode of ring closure.