Amine 1-azido-1-alkene

A solution of 5 mmol of azido alkene in 5 mL of CII2C12 in a dry two-neckcd flask under Ar is cooled to 0°C, then 1.07 g (5.5 mmol) of thexylchloroborane-dimethyl sulfide complex are added slowly and the mixture is stirred for 4 h at r.t. Then 1 mL ol CH3OH is added and the mixture is further stirred for 10 min, the solvents arc evaporated under vacuum, and the residue is taken up in 10 mL of Et20. The amine hydrochloride is extracted with two 10-inL portions of 1 M HCl, then H20 is distilled under vacuum. The crystallized amine hydrochloride is purified by recrystallization. The free amine can be obtained by basic treatment and extraction with solvent. 

The acid-promoted intramolecular Schmidt reaction of azido-alkene 114 is featured in the formal synthesis of gephyrotoxin. Treatment of 114 with trifluoromethanesulfonic acid followed by L-Selectride reduction of the resultant iminium ions 115 and 116 generates a mixture of diastereomeric bromo-amines. The bromide is replaced with acetate ion, and the acetate is reduced to give alcohol 117, a known intermediate in the synthesis of gephyrotoxin. 

Anodic regioselective acetamidosulfeny-lation of alkenes is similarly achieved by oxidation of diphenyldisulfide in acetonitrile [81]. Cyclic enamines, which are intermediates in the oxidation of cyclic N-methoxycarbonyl amines, react in aqueous acetonitrile that contains chloride ions to a-hydroxy- 8-chloro compounds via intermediate chloronium ions [82]. Enolethers undergo a regioselective azidomethoxyla-tion to yield acetals of a-azido carbonyl compounds upon electrolysis in methanol containing sodium azide [83]. The reaction proceeds possibly via addition of an anodicaUy generated azide radical. 

A variety of alkenes undergo azidoiodination with sodium azide, potassium iodide, and Oxone on wet alumina to give azido-iodo compounds regioselectively in high yield (eq 79). These compounds are useful precursors to vinyl azides, amines, and aziridines and are typically synthesized with more expensive and exotic reagents. Similar methods have been used in the iodolac-tonization and iodoetherification of unsaturated carboxylic acids and alcohols to make five- and six-membered lactones, tetrahy-drofurans, and tetrahydropyrans (eq 80). ... 

A number of azido-tethered alkenes and azido-tethered tertiary alcohols similarly generate rearrangement products when treated with TfOH or SnCU followed by a basic or reductive workup. Enamines are obtained when a basic workup is employed whereas the addition of a reducing agent provides tertiary amines (Scheme 7.21) in many cases. 

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