Regiodivergent sulfonylarylation of 1,3-enynes via nickel/photoredox dual catalysis.

Ya Chen,Kun Zhu,Qingqin Huang,Yixin Lu

doi:10.1039/d1sc04320j

Abstract

Catalytic difunctionalization of 1,3-enynes represents an efficient and versatile approach to rapidly assemble multifunctional propargylic compounds, allenes and 1,3-dienes. Controlling selectivity in such addition reactions has been a long-standing challenging task due to multiple reactive centers resulting from the conjugated structure of 1,3-enynes. Herein, we present a straightforward method for regiodivergent sulfonylarylation of 1,3-enynes via dual nickel and photoredox catalysis. Hinging on the nature of 1,3-enynes, diverse reaction pathways are feasible: synthesis of α-allenyl sulfones via 1,4-sulfonylarylation, or preparation of (E)-1,3-dienyl sulfones with high chemo-, regio- and stereoselectivity through 3,4-sulfonylarylation. Notably, this is the first example that nickel and photoredox catalysis are merged to achieve efficient and versatile difunctionalization of 1,3-enynes.

Highlights

Owing to their ambident reactivity and ready availability, 1,3enynes have been exploited as versatile building blocks to access various highly useful molecular architectures,[1] including propargylic compounds,[2] allenes[3] and dienes.[4]
We present a straightforward method for regiodivergent sulfonylarylation of 1,3-enynes via dual nickel and photoredox catalysis
In order to develop regiodivergent sulfonylation of 1,3enynes, we hypothesized that small structural variation of 1,3enynes may provide a straightforward solution: the presence of an alkyl or aryl substituent versus a hydrogen atom may affect the stability of radical species formed during the reaction, which may lead to certain elementary organometallic steps, e.g. migratory insertion, which are more favorable, leading to different regiodivergent pathways

Summary

Introduction

Owing to their ambident reactivity and ready availability, 1,3enynes have been exploited as versatile building blocks to access various highly useful molecular architectures,[1] including propargylic compounds,[2] allenes[3] and dienes.[4]. With the optimized reaction conditions in hand, we investigated the substrate scope for the 1,4-sulfonylarylation of 1,3enynes, rst focusing on the variation of 1,3-enyne structures, and the results are summarized in Scheme 1. The C2-substituents for 1,3-enynes were not limited to aryls, 1,3-enynes bearing a 2-methyl group could be employed, and the allene products were obtained in moderate to high yields (4i–4m).

Results

Conclusion