The radical-mediated carboazidation of terminal alkenes using electrophilic alkanesulfonyl azides is reported. A single reagent delivers the necessary electrophilic alkyl radical as well as the azido group, and good yields are obtained by using a moderate excess of the carboazidating reagent (1.5-2 equiv). Interestingly, in addition to the starting sulfonyl azide, this method requires only the use of a radical initiator, di-tert-butyldiazene. In terms of atom economy, this azide transfer reaction is close to ideal, as SO2 (1 equiv) is the only side product. The synthetic potential of this process has been demonstrated by a formal synthesis of the alkaloid lepadiformine C.

The direct catalytic asymmetric aldol reaction offers efficient access to β-hydroxy carbonyl entities. Described is a robust direct catalytic asymmetric aldol reaction of α-sulfanyl 7-azaindolinylamide, thus affording both aromatic and aliphatic β-hydroxy amides with high ee values. The design of this transformation features a cooperative interplay of a soft and a hard Lewis acid, which together facilitate the challenging chemoselective enolization by a hard Brønsted base.

The catalyst comprising Cu(ii)/chiral hydroxamic acid was found to play a bifunctional role in the direct aldol reaction of α-N3 amide to alkynyl CF3 ketones.

A direct aldol reaction of an α-azido 7-azaindolinylamide, promoted by a Cu-based cooperative catalyst, is documented. Aromatic aldehydes bearing an ortho substituent exhibited diastereodivergency depending on the nature of the chiral ligands used. Smooth reactions with ynals highlighted the broad substrate scope. A vicinal azido alcohol unit in the product allowed direct access to the corresponding aziridine and facile hydrolysis of the 7-azaindolinylamide moiety furnished enantioenriched β-hydroxy-α-azido carboxylic acid derivatives.

Recent advances in radical azidation using sulfonyl azides are presented. For instance, radical carboazidation using α-iodoketones, desulfitative carboazidation, and antiMarkovnikov hydroazidation of alkenes are described. These novel methods tolerate a large number of functional groups and allow the synthesis of organic azides that would be difficult to synthesize otherwise. The transformation of the azides using reductive processes as well as a Schmidt reaction under nonacidic conditions were used to synthesize alkaloids including indolizidine 167B, monomorine I, cylindricine C, and lepadiformine C.