Regioselectivity Study of Contrasteric Aromatic Claisen Rearrangements and Their Utilization in the Total Syntheses of 5-Hydroxymellein and Botyroisocoumarin A.

ABSTRACT: In this study, we present data on the regioselectivity of aromatic Claisen rearrangements with meta-substituted benzenes. A variety of gentisic acid, tetralin, and m-salicylamide derivatives were synthesized to test the potential of an internal base to direct the regioselectivity of ortho-alkylation. A key mechanistic insight hinges on a reversible [3,3]-sigmatropic rearrangement step, supported by ¹H NMR studies of the isomerization of a Z to E crotyl group. This evidence supports the potential for the keto-enol tautomerization step of the aromatic Claisen rearrangement to be the rate-determining step. A ¹³C NMR study shows that this kinetic insight can be used to direct regioselectivity by correlating the carbonyl carbon shifts of

SUBMITTER: Tanas DK 

PROVIDER: S-EPMC12455646 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature