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

Abstract

The trapping of racemic polar carbometallic species with (-)-menthyl ( S)- p-toluenesulfinate (Andersen's reagent) typically proceeds with a very low level of resolution. In this paper, we describe a strategy that allows access to highly atropo-enriched and functionalizable biphenyls by means of Andersen's reagent under kinetic resolution conditions. In particular, useful enantiopure 2-iodobiphenyls could be obtained and were employed in a challenging hypervalent iodine-catalyzed oxidation reaction.

Chiral Hypervalent Iodines: Active Players in Asymmetric Synthesis

“…More recently, Panossian, Leroux, and co-workers investigated a new methodology to prepare this family of chiral iodoarenes by means of an unusual kinetic resolution. 161 As it has been already exposed, for many years, α-oxidation of ketones has been directly assessed from carbonyl compounds and diverse chiral hypervalent iodine catalysts or precursors of those. However, in 2014, Wirth and co-workers 162 published the use of silyl enol ethers in the asymmetric α-functionalization of ketones promoted by a chiral hypervalent iodine reagent (Scheme 32).…”

“…Furthermore, a set of ketones worked in similar results and even other oxygen-containing nucleophiles such as mesylates or diphenylphosphates were successfully further evaluated (Scheme ). More recently, Panossian, Leroux, and co-workers investigated a new methodology to prepare this family of chiral iodoarenes by means of an unusual kinetic resolution …”

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 ) .…”

Synthesis of 2,2′-Dihalobiaryls via Cu-Catalyzed Halogenation of Cyclic Diaryliodonium Salts

“…2,2′-Dihalobiaryls are versatile synthetic intermediates that can be used in a variety of palladium-catalyzed and copper-catalyzed cross-coupling reactions or easily undergo nucleophilic reactions (trapping with phosphorus or other heteroatom electrophiles) through metal–halogen exchange (Scheme a). , 2,2′-Diiodobiaryls also can be converted into hypervalent iodine catalysts, which are widely used in organic catalytic reactions as environmentally friendly catalysts. , Furthermore, many of them are important structural motifs of biologically active molecules. − Compared with their widespread applications in various aspects, only limited synthetic methods of 2,2′-dihalobiaryls have been reported to date. The most frequently used methods are the Sandmeyer reaction or oxidative coupling reaction of iodo-substituted electron rich benzenes under relatively harsh conditions. , Therefore, the development of general methods for the efficient synthesis of 2,2′-dihalobiaryls is of great importance.…”