# HMPA-Enabled Direct γ′-Arylation of Cyclic Vinylogous Esters

## TL;DR

A new palladium-catalyzed method enables selective γ′-arylation of cyclic vinylogous esters using HMPA as a regioselectivity additive.

## Contribution

A Pd-catalyzed γ′-arylation method with HMPA for regioselective modification of cyclic vinylogous esters is introduced.

## Key findings

- The method works with a wide range of (hetero)aryl bromides and CVE substrates.
- γ′-aryl CVEs can be converted to α-arylcycloalkenones via Stork–Danheiser transposition.
- Pd(dba)2/cataCXium A and HMPA enable regioselective γ′-arylation.

## Abstract

Controlling regioselectivity in deprotonative arylation
of conjugated
carbonyl systems remains a longstanding challenge. We report a Pd-catalyzed
γ′-arylation of cyclic vinylogous esters (CVEs), enabled
by Pd­(dba)2/cataCXium A and hexamethylphosphoramide (HMPA)
as a regioselectivity-governing additive. The method accommodates
a broad range of (hetero)­aryl bromides and CVE substrates. The resulting
γ′-aryl CVEs were further converted to α-arylcycloalkenones
via Stork–Danheiser transposition.