Nickel‐Catalyzed Enantioselective Synthesis of Dienyl Sulfoxide

Abstract

Sulfoxides are widely used in the pharmaceutical industry and as ligands in asymmetric catalysis. However, the efficient asymmetric synthesis of this structural motif remains limited. In this study, we disclosed a Ni‐catalyzed enantioconvergent reaction that utilizes both racemic allenyl carbonates and β‐sulfinyl esters. Our method employs cheap and more sustainable Ni(II) as a precatalyst and successfully overcomes the challenging poisoning effect and instability of sulfenate generated in situ. This enables the synthesis of a series of dienyl sulfoxides with enantioselectivity of up to 98 % ee. The product exhibits tremendous potential in various applications, including diastereoselective Diels–Alder reactions, coordination with transition metals, and incorporation into medicinal compounds, among others. Using a combination of experimental and computational methods, we have uncovered an interesting associated outersphere mechanism that contrasts with conventional mechanisms commonly observed in asymmetric transition metal catalysis.

Generation of sulfones utilizing β-sulfinyl esters as masked aryl sulfinates under redox-neutral conditions

“…β-Sulfinyl esters have been widely applied as precursors of sulfenate anions 10 through retro-Michael reaction under basic conditions (Scheme 2(a)). 11 A variety of transformations have been achieved based on this chemistry, for example, transition-metal catalyses 12 and alkali metal salt promoted sulfoxidation 13 as well as organo-catalytic protocols. 14 Moreover, thermolysis of β-sulfinyl esters to yield the sulfenic acid intermediate was also reported.…”