Enantioenriched Allylesters via a Copper-Catalyzed Diene Carboesterification with Alkyltrifluoroborates and Carboxylic Acids.

The rapid synthesis of a range of enantioenriched allylic esters is enabled by a new 3-component catalytic enantioselective 1,2-carboesterification of readily available dienes with carboxylic acids and potassium alkyltrifluoroborates. The chiral copper catalyst, formed in situ from Cu(OTf) and (4,4')-2,2'-(cyclopentane-1,1-diyl)bis(4-phenyl-4,5-dihydrooxazole), is implicated in both the generation of alkyl radicals from the alkyltrifluoroborates as well as the enantioselective formation of C-O bonds. Potassium salts of primary and secondary alkyltrifluoroborates as well as several benzylic trifluoroborates, -butyltrifluoroborate, and phenyltrifluoroborate participate in the reaction.

Copper-catalyzed enantioselective alkene carboetherification for the synthesis of saturated six-membered cyclic ethers.

The enantioselective copper-catalyzed oxidative coupling of alkenols with styrenes for the construction of dihydropyrans, isochromans, pyrans and morpholines is reported. A concise formal synthesis of a σ receptor ligand using this alkene carboetherification methodology was demonstrated. Ligand, solvent and base all impact reaction efficiency.

Synthesis of Benzylureas and Related Amine Derivatives via Copper-Catalyzed Three-Component Carboamination of Styrenes.

A direct assembly of secondary benzylureas and related amine derivatives via copper-catalyzed carboamination of styrenes with potassium alkyltrifluoroborates and ureas, anilines, or an amide is reported. Terminal and 1,2-disubstituted alkenes, as well as dienes, participate in this three-component coupling reaction. The reaction mechanism likely involves the addition of an alkyl radical to the styrene, followed by metal-mediated oxidative coupling of the resulting benzylic radical with the amine derivative.