Direct Construction of NOBINsvia Domino Arylation and Sigmatropic Rearrangement Reactions

Abstract

of main observation and conclusion Privileged 2-amino-2'-hydroxy-1,1'-binaphthyl (NOBIN) frameworks were constructed through a novel domino arylation of naphthylhydroxylamines with diarylhalonium salts and sigmatropic rearrangement in a transition metal-free fashion. This protocol bears broad substrate generality and proceeds under mild reaction conditions, affording diversified NOBINs in high efficiency with absolute regiocontrol during the rearrangement process. Optically active product was accessible by chiral N-heterocyclic carbene-catalyzed kinetic resolution in one pot or diastereoselective [3,3]-rearrangement guided by a removable chiral auxiliary. Remarkably, diarylchloronium and diarylbrominium salts have been employed as arylation reagents for the first time in assembling such representative biaryl frameworks.

Sulfonium-aided coupling of aromatic rings via sigmatropic rearrangement

“…As an elegant recent example, Kürti 13 ) and List 14 ) independently reported in 2013 enantioselective benzidine rearrangement of hydrazonaphthalene by using an Akiyama-Terada catalyst, which affords 2,2′-diaminobinaphthyl, a privileged motif for axially chiral catalysts (Scheme 3 a). Similarly, Kürti/Gao 15 – 17 ) and Li/Tan 18 ) reported the coupling reaction of N -naphthylhydroxylamine with naphthyliodonium salts to synthesize racemic 2-amino-2′-hydroxybinaphthyl via sigmatropic rearrangement of in situ generated N , O -dinaphthylhydroxylamine (Scheme 3 b). Currently, the construction of biaryl skeletons via sigmatropic rearrangement is attracting increased attention.…”

Synthesis of structurally diversified BINOLs and NOBINs via palladium-catalyzed C-H arylation with diazoquinones

“…Nonetheless, the extension to the synthesis of biaryls with BINOL and NOBIN scaffolds was rarely involved. Following this line, diarylhalonium salts were then employed by our group as efficient naphthylation reagents for the reaction with naphthylhydroxylamines to construct NOBIN derivatives [6]. However, BINOL and its derivatives remained untouchable through this approach.…”

Copper-Catalyzed Synthesis of Axially Chiral Biaryls with Diaryliodonium Salts as Arylation Reagents

“…As an effective Ar-Ar bond formation method, [3,3]-sigmatropic rearrangement reaction was emerged as an attractive alternative [ 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. In this context, Gao [ 33 ] and our group [ 34 ] independently developed a transition metal-free approach to generate NOBIN derivatives following a domino arylation of naphthylhydroxylamines with diaryliodonium salts and [3,3]-sigmatropic rearrangement. It should be mentioned that moderate yields were normally obtained for Gao’s conditions, while the mixed solvent of dichloromethane and trifluoroethanol was required to improve reaction results.…”