Selenium-π-Acid Catalyzed Oxidative Functionalization of Alkynes: Facile Access to Ynones and Multisubstituted Oxazoles

Unprecedented selenium-catalyzed propargylic oxidation of alkynes is disclosed. Various propargylphosphonates and 3-alkynoates were efficiently converted to valuable ynones via unusual C–C triple bond migration and deselenenylation at a vinyl carbon. By the strategies of tautomerization of enamine intermediate and S_N2 displacement, similar conditions were effective for the oxidative difunctionalization of ynamides to afford multisubstituted oxazoles with high regioselectivity. Mechanistic studies revealed these detailed processes

Catalytic Enantioselective Aminative Difunctionalization of Alkenes

Enantioselective difunctionalization of alkenes offers a straightforward means for the rapid construction of enantioenriched complex molecules. Despite the tremendous efforts devoted to this field, enantioselective aminative difunctionalization remains a challenge, particularly through an electrophilic addition fashion. Herein, we report an unprecedented approach for the enantioselective aminative difunctionalization of alkenes via copper-catalyzed electrophilic addition with external azo compounds as nitrogen sources. A series of valuable cyclic hydrazine derivatives via either [3 + 2] cycloaddition or intramolecular cyclization have been achieved in high chemo-, regio-, enantio-, and diastereoselectivities. In this transformation, a wide range of functional groups, such as carboxylic acid, hydroxy, amide, sulfonamide, and aryl groups, could serve as nucleophiles. Importantly, a new cyano oxazoline chiral ligand was found to play a crucial role in the control of enantioselectivity

Organoselenium-Catalyzed, Hydroxy-Controlled Regio- and Stereoselective Amination of Terminal Alkenes: Efficient Synthesis of 3‑Amino Allylic Alcohols

An efficient route to prepare 3-amino allylic alcohols in excellent regio- and stereoselectivity in the presence of bases by orangoselenium catalysis has been developed. In the absence of bases α,β-unsaturated aldehydes were formed in up to 97% yield. Control experiments reveal that the hydroxy group is crucial for the direct amination