Pd‐Catalyzed Decarboxylative Allylation for Stereoselective Syntheses of Allylic Alcohols bearing a Quaternary Carbon Center

Abstract

Olefins play a vital role in the fields of bioscience, medicine, and chemistry. Stereo-defined olefins are important resource in both chemical laboratory and industry. Using a palladium-catalyzed decarboxylative transformation of vinyl cyclic carbonates, we have developed an efficient and reliable method for the direct construction of highly substituted olefins with the concomitant formation of a new Csp 3 -Csp 3 bond. The desired olefins could be generated in reasonable yields with good stereoselectivities, in contrast to the existing methods, which are usually nonstereoselective. The palladium-catalyzed decarboxylative transformation will undoubtedly provide new synthetic routes for the formation of multi-substituted allylic scaffolds.[a] L. Scheme 2. Scope with 1,3-dicarbonyl partners. Reaction conditions: 1 a (0.1 mmol), Pd catalyst (5 mol%), Ligand (8 mol%), stirring in DCM stirred at 30°C for 4 h.

An Update of Transition Metal-Catalyzed Decarboxylative Transformations of Cyclic Carbonates and Carbamates

“…This concept was first proved by Guo and co-workers using aryl amine nucleophiles toward the formation of highly functionalized (Z)-configured allylic alcohols/amines; the DFT (Density Functional Theory) studies suggested that the formation of a six-membered palladacyclic intermediate is the key for excellent stereocontrol [43]. Apart from amines, various other nucleophiles were demonstrated to be efficient for the syntheses of a huge number of allylic alcohols with excellent stereoselectivity (Scheme 10) [44][45][46][47]. By judicious choice of the palladium catalyst and ligand, the nucleophilic attack could be switched toward the sterically hindered carbon of the palladium allyl intermediate that derived from vinyl carbonate; this concept was first demonstrated by Guo and co-workers in the preparation of chiral α,α-disubstituted allylic aryl amines [48], and later it was further developed by the Khan group in the synthesis of chiral sulfones [49].…”

Pd-Catalyzed Decarboxylative Cycloaddition for the Synthesis of Highly Substituted δ-Lactones and Lactams

“…First, we investigated a model vinyl cyclic carbonate to determine the feasibility of forming the corresponding lactone products via the Pd-catalyzed decarboxylative cycloaddition process (Table ). In preliminary experiments, vinyl cyclic carbonate 1a and the general ligand 1,3-bis­(diphenylphosphino)­propane were exposed to a CO atmosphere under balloon pressure. , …”

“…In this context, many efficient Pd-catalyzed decarboxylation conversions have been reported by Zhang, Kleij, Zhao, and Glorius (Scheme b). We recently reported a Pd-catalyzed allylation to construct allylic amines and alcohols bearing an all-carbon quaternary center. , Herein, we report a practical and reliable strategy for the generation of substituted δ-lactones and lactams through a Pd-catalyzed decarboxylative cycloaddition process (Scheme c). This method successfully forms a C–O and a C–N bond in addition to installing a tetra-substituted double bond that may be further functionalized.…”

Dual Cobalt/Organophotoredox Catalysis for Diastereo- and Regioselective 1,2-Difunctionalization of 1,3-Diene Surrogates Creating Quaternary Carbon Centers

“…Vinylethylene carbonates (VCCs, Scheme d) have recently emerged as versatile substrates in allylic substitution (Scheme d, using NuH) and cycloaddition chemistry (Scheme d, using E + ), delivering compounds with sterically congested stereocenters . Despite these well-established Pd-catalyzed decarboxylative transformations of VCCs, their use as versatile, in situ- generated 1,3-diene reagents remains undeveloped .…”