Efficient Pd‐Catalyzed Regio‐ and Stereoselective Carboxylation of Allylic Alcohols with Formic Acid

Abstract

Formic acid is efficiently used as a C1 source to directly carboxylate allylic alcohols in the presence of a low loading of palladium catalyst and acetic anhydride as additive to afford β,γ-unsaturated carboxylic acids with excellent chemo-, regio-, and stereoselectivity. The reaction proceeds through a carbonylation process with in situ-generated carbon monoxide under mild conditions, avoiding the use of high-pressure gaseous CO. A bisphosphine ligand with a large bite angle (4,5-bis{diphenylphosphino}-9,9-dimethylxanthene, Xantphos) was found to be uniquely effective for this transformation. The regio- and stereoconvergence of this reaction is ascribed to the thermodynamically favored isomerization of the allylic electrophile in the presence of the palladium catalyst.

Palladium-Catalyzed Direct C–H Arylation of 3-Butenoic Acid Derivatives

“…One is the condensation of aryl acetaldehyde with malonic acid and another is through the Wittig reaction of aryl acetaldehyde with 2-(carboxy-ethyl)­triphenylphosphonium bromide as the coupling partner. The research groups of Fu and Wu have transformed cinnamyl alcohol into 4-phenyl-3-butenoic acid derivatives. These methods greatly enrich the synthetic methodology of 4-phenyl-3-butenoic acid derivatives, but the poor availability of prefunctionalized starting material limits the scope of preparing functional-group-substituted 4-aryl-3-butenoic acids.…”

Recent Advances in Metal‐Catalyzed Carbonylation Reactions by Using Formic Acid as CO Surrogate

“…Later on, in 2017 same group utilized allylic alcohols for the synthesis of β,γ‐unsaturated carboxylic acids by using the catalytic system of palladium acetate, Xantphos and formic acid as a CO source. The reaction proceeds via the formation of allyl complexation I of Pd with allylic alcohol, direct regioselective CO insertion, reductive elimination, and acid exchange leads to the formation of β,γ‐unsaturated carboxylic acids along with acetic acid as the only by‐product.…”

Recent developments in carbonylation chemistry using [13C]CO, [11C]CO, and [14C]CO

“…Wu and coworkers have demonstrated this concept by synthesizing 13 C‐labeled aldehydes ( 107 ; Scheme 28A) and formates ( 108 ; Scheme 28B) using palladium catalysis. Fu et al recently used a similar procedure for liberating [ 13 C ]CO in situ from [ 13 C ]HCOOH for accessing 13 C‐labeled carboxylic acids from allylic alcohols ( 109 ; Scheme 28C).…”