[Article Peptides]

Herein we describe a sustainable and efficient photocatalytic method for the stereoselective radical alkylation of chiral sulfinyl imines. By employing readily available non-prefunctionalized radical precursors and the cost-effective TBADT as a direct HAT photocatalyst, we successfully obtain diverse chiral amines with high yields and excellent diastereoselectivity under mild conditions. This method provides an efficient approach for accessing a diverse array of medicinally relevant compounds, including both natural and synthetic α-amino acids, aryl ethyl amines, and other structural motifs commonly found in approved pharmaceuticals and natural product.

An enantioselective chiral phosphoric acid catalyzed formal [4+2] cycloaddition between 2-benzothiazolimines and N-H-1,3-dienecarbamates is described. A divergence in reaction pathways was observed depending on the dienes employed. The reaction performed with 4-substituted dienes produced benzothiazolopyrimidines as major product in yields ranging from 42 to 67%, as single diastereoisomer and with enantioselectivity between 93 and 99%. The same reaction performed with 3- substituted dienes, however, gave highly enantioenriched 1,2,3,4-tetrahydroquinolines as the major products albeit with moderate diastereoselectivity.