Diastereodivergent Synthesis of Chiral α‑Aminoketones via a Catalytic O–H Insertion/Barnes–Claisen Rearrangement Reaction

A tandem asymmetric catalytic O–H insertion/Barnes–Claisen rearrangement reaction from 4-acyl-1-sulfonyl-1,2,3-triazoles with allylic alcohols is developed for the purpose of synthesizing all possible stereomers of α-aminoketones under mild conditions. It is found that 4-acyl-1-sulfonyl-1,2,3-triazoles not only form rhodium carbenoids with higher electrophilicity under milder conditions in comparison to 4-aryl-1-sulfonyl-1,2,3-triazoles but also afford another coordination model during the N,N′-dioxide/metal complex promoted asymmetric Barnes–Claisen rearrangement. In addition, two different O–H insertion intermediates have been separated and their transformations have been researched. On the basis of control experiments and previous works, a possible mechanism is proposed to illustrate the reaction process and the induction of the stereoselectivity.