Decarboxylative Allylation of Glyoxylic Acids with Diallyl Carbonate

Abstract

A catalyst system consisting of Pd(PPh3)4 and P(pTol)3 was found to effectively promote the intermolecular decarboxylative coupling of α‐oxocarboxylic acids with diallyl carbonate to give α,β‐unsaturated ketones. The key advantage of the new reaction protocol is that preformation of the allyl esters is not required. The reaction is believed to proceed via phosphane‐mediated decarboxylation of the α‐oxocarboxylates, leading to acyl anion equivalents that are allylated within the coordination sphere of the palladium catalyst. Under the reaction conditions, the double bond then migrates into conjugation with the carbonyl group.

Transition‐Metal‐Free Formal Decarboxylative Coupling of α‐Oxocarboxylates with α‐Bromoketones under Neutral Conditions: A Simple Access to 1,3‐Diketones

“…(1)]. 2a After this seminal work, various sp 2 ‐hybridized carbon derivatives, including allyls,2d,e (hetero)arenes,2f–j enamides,2k and formamides,2l have been successfully acylated using this strategy. However, no example involving sp 3 ‐hybridized carbon centers has been reported. …”

Synthesis of Enones and Enals via Dehydrogenation of Saturated Ketones and Aldehydes

“…( E )‐2‐methyl‐1‐(p–tolyl)but‐2‐en‐1‐one (2 n) Prepared according to general procedure to afford as colorless oil (65% yield). R f =0.57 (EtOAc/hexanes 1:10).…”

Transition‐Metal‐Free Formal Decarboxylative Coupling of α‐Oxocarboxylates with α‐Bromoketones under Neutral Conditions: A Simple Access to 1,3‐Diketones

“…(1)]. 2a After this seminal work, various sp 2 ‐hybridized carbon derivatives, including allyls,2d,e (hetero)arenes,2f–j enamides,2k and formamides,2l have been successfully acylated using this strategy. However, no example involving sp 3 ‐hybridized carbon centers has been reported. …”