The catalytic enantioselective three-component Petasis reaction among salicylaldehydes, amines, and organoboronic acids with a newly designed thiourea-binol catalyst is presented. A broad range of alkylaminophenols can be obtained in good yield (up to 92%) and good to high enantioselectivity (up to 95% ee). A possible reaction pathway for this catalytic enantioselective Petasis reaction is tentatively proposed.As a multicomponent reaction, 1 the Petasis reaction enjoys a history of nearly two decades and makes a significant contribution to the preparation of an assortment of compounds depending on the nature of the aldehyde component involved. 2 Among them, R-amino acids starting from glyoxylic acid and derivatives, R-hydroxyl amines starting from glycolaldehyde and derivatives, and alkylaminophenols starting from salicylaldehyde and derivatives are the most easily accessible. 3 In particular, studies on asymmetric induction by using various chiral reactants have achieved remarkable success in this area. 2b,2d,4 However, to date, there are only three examples concerning the catalytic enantioselective Petasis reaction reported by Takemoto 5 and Schaus, 6 respectively (Scheme 1, eqs 1À3). Notably, the three existing catalytic †

A biocatalytic approach towards a range of 4‐aryloxazolidinones is developed using a halohydrin dehalogenase from Ilumatobacter coccineus (HheG) as biocatalyst. The method is based on the HheG‐catalyzed α‐position regioselective ring‐opening of styrene oxide derivatives with cyanate as a nucleophile, producing the corresponding 4‐aryloxazolidinones in moderate to good yields. Synthesis of enantiopure 4‐aryloxazolidinones is also achievable using chiral epoxide materials.magnified image

Halohydrin dehalogenases are usually recognized as strict b-position regioselective enzymes in the nucleophile-mediated ring-opening of epoxides. Here we found the HheG from Ilumatobacter coccineus exhibited excellent a-position regioselectivity in the azide-mediated ring-opening of styrene oxide derivatives 1a-1k, producing the corresponding 2-azido-2-aryl-1-ols 2a-2k with the yields up to 96%.Scheme 1 HHDH-catalyzed a-position and b-position regioselective ring-opening of epoxides with azide.