Tungsten‐Catalyzed Regio‐ and Enantioselective Aminolysis of trans‐2,3‐Epoxy Alcohols: An Entry to Virtually Enantiopure Amino Alcohols

Abstract

The first catalytic enantioselective aminolysis of trans‐2,3‐epoxy alcohols has been accomplished. This stereospecific ring‐opening process was efficiently promoted by a tungsten/bis(hydroxamic acid) catalytic system, furnishing various anti‐3‐amino‐1,2‐diols with excellent regiocontrol and high enantioselectivities (up to 95 % ee). Moreover, virtually enantiopure 3‐amino‐1,2‐diols could be obtained by the sequential combination of two reactions that both involve the use of a chiral catalyst.

Chiral Hydroxamic Acid Ligands in Asymmetric Synthesis: The Evolution of Metal‐Catalyzed Oxidation Reactions

“…In this context, Yamamoto reported in 2014 a catalytic regioselective and stereospecific ring opening of 2,3epoxy alcohols promoted by achiral tungsten salts. [51] Then, they described the enantioselective aminolysis of 2,3-epoxy alcohols with various amines as the nucleophiles using the tungsten-bishydroxamic acid catalytic system , [52] which can perform both the epoxidation and the ring-opening reaction thus providing the enantiopure 3-amino-1,2-diols. The sub- strate scope showed that all the reactions proceeded at 55 °C in the presence of a W-BHA catalytic system (2.5 or 5 mol%), with enantioselectivities ranging from 40 to 95 %.…”

“…The epoxidation followed by the ring‐opening reaction was also studied, and this strategy's implementation allows optically pure amino alcohols in up to 99.8 % enantiomeric excess (Scheme 38). [52] …”

Synthesis and medicinal chemical characterisation of antiproliferative O,N-functionalised isopulegol derivatives

“…Sharpless) epoxidation [46][47][48][49][50][51][52] followed by C-3 regioselective ringopening of 2,3-epoxy alcohols with amines. [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68] In the last decade, a metal-and solvent-free protocol, 69 involving C-3 selective ring-opening of 2,3-epoxy alcohols with amines catalysed by W-salts, 70 b-cyclodextrin, 66 MgCl 2 , 71 or the tungsten/ bis(hydroxamic acid) system 72 as well as a two-step combined epoxidation/ring-opening methodology 73 were shown to generate virtually enantiopure functionalised 3-amino-1,2diols. The ring-opening of chiral epoxy alcohols with nucleophiles [74][75][76][77][78][79][80][81][82] provides direct access to versatile chiral building blocks for the synthesis of natural products and synthetic analogues with promising biological activities, 83,84 such as cardiovascular, 85 antibacterial 86,87 and sedative effects.…”