Ring-Opening of Vinylcyclopropane-1,1-dicarboxylates by Boronic Acids under Ligandless Palladium Catalysis in Neat Water

Abstract

We report a highly efficient ring-opening reaction of vinylcyclopropanes by boronic acids in water, using palladium nanoparticles formed from Pd(OAc)2 under ligandless conditions. Unsubstituted vinylcyclopropanes provide linear addition products with high selectivity, while a switch in regioselectivity to branched products is observed for aryl-substituted vinylcyclopropanes.

Synthetic applications of vinyl cyclopropane opening

“…A new palladium catalyzed vinyl cyclopropane opening was reported by Hyland in 2015. 34 In this example, vinyl cyclopropanes 16 react with boronic acids 72 in water under Pd(II) catalysis without the need of ligands. In the proposed reaction mechanism, the authors claim that first Pd(II) VII reacts with the boronic acid 72 to generate Pd(0) nanoparticles.…”

Solvated Nickel Complexes as Stoichiometric and Catalytic Perfluoroalkylation Agents**

“…Such reaction conditions have commonly been referred to as "ligandless" conditions in other systems. [22][23][24][25][26][27][28] Previously,w ef ound that [PPh 4 ][2]a nd [PPh 4 ] 2 [3] (Scheme 1) could be synthesized by the addition of one and two equivalents of "A gCF 3 "t o1 in the presence of [PPh 4 ]Cl. [29] Thee lectronic properties of 2 and 3 were extensively studied through the use of density functional theory (DFT) calculations,s pectroscopy-oriented configuration interaction (SORCI) calculations,X -ray absorption spectroscopy,a nd cyclic voltammetry.…”

Solvated Nickel Complexes as Stoichiometric and Catalytic Perfluoroalkylation Agents**

“…Given these considerations, we became interested in developing new fluoroalkylation methods with nickel that employed solvent as the only coordinating ligand. Such reaction conditions have commonly been referred to as “ligandless” conditions in other systems [22–28] …”

“…Such reaction conditions have commonly been referred to as "ligandless" conditions in other systems. [22][23][24][25][26][27][28] Previously,w ef ound that [PPh 4 ][2]a nd [PPh 4 ] 2 [3] (Scheme 1) could be synthesized by the addition of one and two equivalents of "AgCF 3 "t o1 in the presence of [PPh 4 ]Cl. [29] Thee lectronic properties of 2 and 3 were extensively studied through the use of density functional theory (DFT) calculations,s pectroscopy-oriented configuration interaction (SORCI) calculations,X -ray absorption spectroscopy,a nd cyclic voltammetry.…”