In this letter, an efficient method for the photolytic generation of difluoromethyl radicals from [bis(difluoroacetoxy)iodo]benzene reagents is described. The present approach enables the introduction of difluoromethyl groups into various heteroarenes under mild conditions in the absence of any additional reagents or catalysts.

The 1,2-diamine (vicinal diamine) motif is present in a number of natural products with interesting biological activity and in many chiral molecular catalysts. The efficient and stereocontrolled synthesis of enantioenriched vicinal diamines is still a challenge to modern chemical methodology. We report here both syn- and anti-selective asymmetric direct Mannich reactions of N-protected aminoacetaldehydes with N-Boc-protected imines catalyzed by proline and the axially chiral amino sulfonamide (S)-3. This organocatalytic process represents the first example of a Mannich reaction using Z- or Boc-protected aminoacetaldehyde as a new entry of α-nitrogen functionalized aldehyde nucleophile in enamine catalysis. The obtained optically active vicinal diamines are useful chiral synthons as exemplified by the formal synthesis of (-)-agelastatin A.

A practical approach to radical C-H bond functionalization by the photolysis of a hypervalent iodine(iii) reagent is presented. The photolysis of [bis(trifluoroacetoxy)iodo]benzene (PIFA) leads to the generation of trifluoroacetoxy radicals, which allows the smooth transformation of various alkylbenzenes to the corresponding benzyl ester compounds under mild reaction conditions.

In contrast to the well-known [2 + 2] photocycloadditions between C═O and C═C bonds, the participation of C═N bonds in such reactions is relatively rare. In this paper, the unprecedented UV-light-induced [2 + 2] cycloadditions between N-arylsulfonylimines and styrene derivatives or benzofurans are described. This photolytic reaction allows the highly stereoselective construction of azetidine derivatives under ambient conditions.