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We report a selenium-catalyzed diamination of dienes using sulfamates as a convenient nitrogen source. This reaction proceeds regioselectively for 1,2-addition at the less substituted alkene, without the need for a tethered diamine. We also report the first diamination of dienyl phosphates and tosylates, affording synthetically useful α,β-diaminoketone derivatives with high syn diastereoselectivity. Density functional theory calculations support a mechanism proceeding via [4+2] cycloaddition of the diene with a selenium bis(imide), followed by ring-opening aminolysis and [2,3]-sigmatropic rearrangement. 

Abstract A transition metal‐free Se‐catalyzed C−H amination protocol for α’‐amination of enol derivatives has been developed. This reaction can be used to functionalize a wide variety of oxygen‐ and halogen‐substituted alkenes spanning a vast range of nucleophilicities, giving α’‐aminated enol derivatives with high regioselectivity. Amination ofE/Zmixtures of alkenes proceeds stereoconvergently to give the (Z)‐enol derivatives exclusively. Mechanistic studies revealed that the relative reactivity and α’‐regioselectivity of these transformations is determined by substantial resonance donation to the heteroatom‐bound carbon in the transition state. These products participate in traditional reactions of enol derivatives, allowing for efficient functionalization of both α‐ and α’‐positions from a single enol derivative with high diastereocontrol. 

We report a diastereoconvergent synthesis of anti -1,2-amino alcohols bearing N-containing quaternary stereocenters using an intermolecular direct C–H amination of homoallylic alcohol derivatives catalyzed by a phosphine selenide. Destruction of the allylic stereocenter during the selenium-catalyzed process allows selective formation of a single diastereomer of the product starting from any diastereomeric mixture of the starting homoallylic alcohol derivatives, eliminating the need for the often-challenging diastereoselective preparation of starting materials. Mechanistic studies show that the diastereoselectivity is controlled by a stereoelectronic effect (inside alkoxy effect) on the transition state of the final [2,3]-sigmatropic rearrangement, leading to the observed anti selectivity. The power of this protocol is further demonstrated on an extension to the synthesis of syn -1,4-amino alcohols from allylic alcohol derivatives, constituting a rare example of 1,4-stereoinduction. 

Herein we report an intermolecular propargylic C–H amination of alkynes. This reaction is operationally convenient and requires no transition metal catalysts or additives. Terminal, silyl, and internal alkynes bearing a wide range of functional groups can be aminated in high yields. The regioselectivity of amination for unsymmetrical internal alkynes is strongly influenced by substitution pattern (tertiary > secondary > primary) and by relatively remote heteroatomic substituents. We demonstrate that amination of alkynes bearing α-stereocenters occurs with retention of configuration at the newly-formed C–N bond. Competition experiments between alkynes, kinetic isotope effects, and DFT calculations are performed to confirm the mechanistic hypothesis that initial ene reaction of a selenium bis(imide) species is the rate- and product-determining step. This ene reaction has a transition state that results in substantial partial positive charge development at the carbon atom closer to the amination position. Inductive and/or hyperconjugative stabilization or destabilization of this positive charge explains the observed regioselectivities. 

A new selenophosphoramide-catalyzed diamination of terminal- and trans -1,2-disubstituted olefins is presented. Key to the success of this transformation was the introduction of a fluoride scavenger, trimethylsilyl trifluoromethanesulfonate (TMSOTf), to prevent a competitive syn -elimination pathway, as was the use of a phosphoramide ligand on selenium to promote the desired substitution reaction. A screen of catalysts revealed that more electron-rich phosphine ligands resulted in higher yields of the desired product, with selenophosphoramides giving the optimal results. A broad range of substrates and functional groups were tolerated and yields were generally good to excellent. For ( E )-1,2-disubstituted olefins, diastereoselectivities were always high, giving exclusively anti products. The conditions were also applied to substrates bearing internal nucleophiles such as esters and carbonates, giving rise to 1,2-aminoesters and cyclic carbonates, respectively.