Unactivated aziridines are the core substructures in a plethora of bioactive natural products and serve as building blocks in organic synthesis. Despite this, very limited methods are available to access them directly from olefins, as most of the known methods are devoted to their activated counterparts. Herein, we have developed a highly efficient Rh(II)-catalyzed method for the direct preparation of unactivated aziridines from olefins using O-(sulfonyl)hydroxylamines as the aminating agent. The reactions proceed with a high stereospecificity.

The first N-heterocyclic carbene (NHC)-organocatalytic tandem [1,2]-phospha-Brook/[1,4]-phosphate rearrangement is reported. Acyl phosphonates, unlike acyl silanes that are well-exploited, make entry as the acyl anion precursors under NHC catalysis. The reactions proceed with absolute chemoselectivity via cross-acyloin condensation between acyl phosphonates and aldehydes giving the products α-ketophosphates in good to excellent yields. The challenging (enolizable) aliphatic-aliphatic substrates coupling also furnished the desired product in a good yield.

The stereoselective oxidative rearrangement of disubstituted unactivated olefins has been achieved using a hypervalent iodine(III) reagent. The aryl group undergoes 1,2migration to give tert-α-arylated aldehydes (as acetals). The preparation of these aldehydes/acetals, especially containing a tert-benzylic stereocenter, has remained challenging. This migration-based method provides a complementary approach over the known α-substitution-based methods for accessing this class of molecules.