Atroposelective Synthesis of Axially Chiral All‐Benzenoid Biaryls by the Gold‐Catalyzed Intramolecular Hydroarylation of Alkynones

Abstract

The cationic gold(I)/(R)‐xyl‐binap complex was shown to catalyze the atroposelective intramolecular hydroarylation of alkynones to produce enantioenriched axially chiral all‐benzenoid biaryls, 4‐aryl‐2‐naphthol derivatives, with up to 67 % ee. The reaction of a racemic alkynone in the presence of the same gold(I) catalyst also afforded the corresponding axially chiral all‐benzenoid biaryl in excellent yield with 70 % ee.

Enantioselective Synthesis of Fully Benzenoid Single and Double Carbohelicenes via Gold‐Catalyzed Intramolecular Hydroarylation

“…However, there was concern as to whether the reaction would proceed even if the highly nucleophilic 2‐aminonaphthalene moiety is replaced to less nucleophilic 2‐alkylnaphthalene moiety. Pleasingly, we recently succeeded in the enantioselective synthesis of biaryls by the gold‐catalyzed intramolecular hydroarylation of alkynones . In this paper, we disclose the enantioselective synthesis of fully benzenoid single and double carbo[6]helicenes 6 and 7 via the gold‐catalyzed intramolecular hydroarylation (Scheme ).…”

Tandem Reactions of Ynones: via Conjugate Addition of Nitrogen‐, Carbon‐, Oxygen‐, Boron‐, Silicon‐, Phosphorus‐, and Sulfur‐Containing Nucleophiles

“…Other arenes, like furans, oxazoles, naphthalene, or benzenes with electron‐donoring groups, have also been explored as substrates in the intramolecular cyclization (Scheme ).…”

Stereoselective arene formation

“…This approach was elegantly utilized by Tanaka for the atroposelective synthesis of phenanthrenes via a stereoselective arene-forming hydroarylation of racemic propargylic ketones (Scheme 22). 44 Unsymmetrically substituted biaryls were obtained in exquisite yields and enantioselectivities of up to 70% enantiomeric excess were achieved.…”