Transition‐Metal‐Free Synthesis of a Known Intermediate in the Formal Synthesis of (–)‐Steganacin

Abstract

The formal synthesis of the two enantiomers of a natural, axially chiral biaryl, steganacin, is reported. The previously developed atropo‐diastereoselective coupling of an aryne and an aryllithium (“aryne coupling”) allows for this synthesis. In each step, the axial configuration of the biaryl could be maintained. The key intermediate, identified previously, was accessed without using transition metals, which demonstrates the potential of the aryne coupling reaction as a complementary or alternative to transition‐metal‐catalyzed coupling reactions.

Stereoselectivity Switch in the Trapping of Polar Organometallics with Andersen’s Reagent—Access to Highly Stereoenriched Transformable Biphenyls

“…On the other hand, employing 2 equiv of the bulkier t -BuLi instead of 1 equiv of BuLi only afforded the starting material. This result is coherent with related findings by our group in the case of a hindered iodine atom ortho to the aryl–aryl bond …”

Transition‐Metal‐Free Heterobiaryl Synthesis via Aryne Coupling

“…In this context, Leroux et al reported an efficient transition metal free aryl‐aryl coupling protocol, the so‐called “Aryne coupling” reaction . Very recently, we extended the reaction to the construction of hetaryl‐aryl backbones, developing thus the “(Het)‐Aryne” version of the reaction (Scheme ) .…”

“…In this context, Leroux et al reported an efficient transition metal free aryl-aryl coupling protocol, the so-called "Aryne coupling" reaction. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] Very recently, we extended the reaction to the construction of hetaryl-aryl backbones, developing thus the "(Het)-Aryne" version of the reaction (Scheme 1). [44] However, our study essentially focused on the thiophene ring as a model partner.…”