Hydroboration with chloramine

V-trimethylsilyl protected olefinic amines and terminal diolefins have been successfully hydroborated with dimethylborane. The resulting organoborane was treated with in situ-generated chloramine or chloralkylamine to produce isomerically pure diamines or N-substituted unsymmetrical diamines in good yields [26] (Scheme 9). 

Similarly, N-(p-toluenesulfonyl)-protected primary amines have been prepared using two different protocols, via hydroboration - amination with chloramine-T... 

After hydroboration, oxidation of radioiodide is performed with Chloramine-T, forming HO-I, which then adds to the C-B bond. The reactivity of the C-B bonds depends on the position of boron, which can either be formed from a terminal double bond or from an internal alkene. While the former case produces two radioiodinated compounds, the latter forms only one. Therefore, dicyclohexylborane is used for the hydroboration step. Both reactions, hydroboration of the alkene and radioiodination can be performed in one sequence without isolating the intermediately formed trialkylborane. 

Organoboranes react with a mixture of aqueous NH3 and NaOCl to produce primary amines. It is likely that the actual reagent is chloramine NH2CI. Chloramine itself,hydroxylamine-O-sulfonic acid in diglyme, and trimethyl-silyl azide " also give the reaction. Since the boranes can be prepared by the hydroboration of alkenes (15-16), this is an indirect method for the addition of NH3 to a double bond with anti-Markovnikov orientation. Secondary amines can be prepared by the treatment of alkyl- or aryldichloroboranes or dialkylchlorobor-anes with alkyl or aryl azides. 

The hydroboration amination sequence in diglyme is a general procedure for the conversion of olefins to primary amines without rearrangement and with predictable stereochemistry.5 An alternative procedure, using tetrahydrofuran as solvent and either hydroxylamine-O-sulfonic acid or chloramine, is applicable with terminal olefins and relatively unhindered internal and alicyclic olefins.6 O-Mesitylenesulfonylhydroxylamine also gave desired amines in comparable yield.7 Alternative procedures for the hydroboration of olefins use commercially available solutions of di-borane in tetrahydrofuran8 or dimethylsulfide.9... 

RCH=CHi — RCH CH Hi. Brown and co-workers " found that an alkylborane resulting from hydroboration of an olefin reacts readily with either chloramine or hydroxylamine-O-sulfonic acid to form the corresponding amine in yield of 50-60%. For example, norbomene yields exo-norbornylamine. 

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