Wang Huamin, Erchinger Johannes E, Lenz Madina, Dutta Subhabrata, Daniliuc Constantin G, Glorius Frank
Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 36, 48149 Münster, Germany.
J Am Chem Soc. 2023 Nov 1;145(43):23771-23780. doi: 10.1021/jacs.3c08512. Epub 2023 Oct 18.
Given the importance of cyclic frameworks in molecular scaffolds and drug discovery, it is intriguing to precisely forge and manipulate ring systems in synthetic chemistry. In this field, the intermolecular synthesis of densely substituted cyclobutanes with precise diastereocontrol under simple reaction conditions remains a challenge. Herein, a photoredox strategy for the difunctionalization of bicyclo[1.1.0]butanes (BCBs) under high regio- and -selectivity is disclosed. C-S σ-bond cleavage of partially unsaturated sulfur-containing bifunctional reagents in an overall strain-release-driven process enables the thio-alkynylation, -alkenylation, and -allylation of BCBs under mild conditions and demonstrates the generality of this protocol. Mechanistic studies suggest that the intermediacy of cyclic distonic radical cations might be key for the efficient scission of C-S σ-bonds and the origin of diastereoselectivity.
鉴于环状骨架在分子支架和药物发现中的重要性，在合成化学中精确构建和操纵环系统是很有趣的。在该领域，在简单反应条件下以精确的非对映体控制进行密集取代环丁烷的分子间合成仍然是一项挑战。在此，公开了一种在高区域和立体选择性下对双环[1.1.0]丁烷（BCB）进行双官能化的光氧化还原策略。在一个总体应变释放驱动的过程中，部分不饱和含硫双官能试剂的C-S σ键断裂使得BCB在温和条件下能够进行硫代炔基化、烯基化和烯丙基化反应，并证明了该方案的通用性。机理研究表明，环状张力自由基阳离子的中间体可能是C-S σ键有效断裂和非对映选择性起源的关键。
