Catalytic Asymmetric Benzidine Rearrangement

Abstract

Eine chirale Brønsted‐Säure katalysiert die asymmetrische Benzidin‐Umlagerung von N,N′‐Dinaphthylhydrazinen. Eine Reihe von elektronisch und strukturell verschiedenen axial‐chiralen 2,2′‐Binaphthyldiaminen (BINAMs) wurde mit hoher Enantioselektivität hergestellt.

Practical Organocatalytic Synthesis of Functionalized Non‐C2‐Symmetrical Atropisomeric Biaryls

“…As part of an ongoing program in our group to develop new and practical TM-free direct arylation methods for the preparation of highly functionalized symmetrical and unsymmetrical biaryls [5, 10b] , we became intrigued by the possibility of using quinone and iminoquinone monoacetals [11] as arylating agents to access both BINOL/NOBIN-type of functionalized biaryls, that are atropoisomeric but non-C 2 -symmetrical, from phenols and naphthols under organocatalytic conditions (Figure 2). The coupling of quinone monoacteals with alkoxyarenes has only been demonstrated in the presence of solid acids such as montmorillonite (MT) clay.…”

Highly Enantioselective Kinetic Resolution of Axially Chiral BINAM Derivatives Catalyzed by a Brønsted Acid

“…There have only been a few synthetic attempts toward enantiopure BINAM derivatives, including a direct catalytic enantioselective oxidative homocoupling of 2‐naphthylamines with modest results6 and [3,3]‐sigmatropic rearrangement promoted by a camphor sulfonic acid with poor enantioselectivity 7. Quite recently, with Brønsted acids as efficient organocatalysts, the [3,3]‐sigmatropic rearrangement strategy was further improved by the groups of List8a and Kürti,8b respectively (Scheme ). Over the past several decades, the kinetic resolution9 of racemic starting materials has been one of the most powerful and reliable strategies for the synthesis of enantiopure compounds in both academia and industry, which would serve as a valuable complementary approach to the traditional synthetic methods, such as asymmetric synthesis and classic resolution.…”

Organocatalysts for enantioselective synthesis of fine chemicals: definitions, trends and developments

“…It is in this context that List and co-workers paid particular attention onto chiral BA catalysts, developing a wide set of chiral phosphoric acids, whose utility is well recognized. The (S)-TRIP (57, Figure 15c), a binaphtyl phosphoric acid, is the most relevant example of this series since it has been [78][79][80][81]. Chiral BAs have shown particularly successful performances in the acetalization reaction [82,83,84].…”