Bromomethyl aziridine

D hooghe, M. Van Brabandt, W. De Kimpe, N. New Synthesis of Propargylic Amines from 2-(Bromomethyl)aziridines. Intermiediacy of 3-Bromoazetidinium Salts. /. Org. Chem. 2004, 69, 2703-2710. 

N-(y- Ialoalkyl) imines undergo cyclization to aziridines upon treatment with sodium borohydride in methanol548. Dibromoketimines can be readily cyclized to give (2-bromomethyl)aziridines in good yields under similar conditions (equation 151)549. 

Finally, some rather interesting but esoteric methyleneaziridines (e.g., 761) have been prepared via the 1,2-dehydro-bromination of 2-(bromomethyl)aziridines 760 under carefully controlled conditions (Scheme 183) <1997JOC2448>. 

Elimination. Sometimes zinc dust alone is inadequate for achieving organic reactions. Surface modification can have dramatic effects. The Zn-Cu couple is useful for the synthesis of chiral allylic alcohols from epoxy tosylates and of ally-lamines from 2-(bromomethyl)aziridines (with sonication). 

Extension to a bromomethyl aziridine was developed with partial success, leading to allylamines (Eq. 70).309... 

Reaction of the lithium anion of trimethylsilylacetonitrile with iV-benzyl-2-(bromomethyl)aziridines, followed by trimethylsilyl group cleavage by means of an aqueous NaOH workup, gave 2-cyanoethylaziridines in 65% yield (eq 17). ... 

To a solution of 3.60 g 2-(bromomethyl)-l-((4-methylphenyl)methyl)aziridine (15 mmol) in 50 mL acetonitrile was added 2.56 g benzyl bromide (15 mmol). After the solution was refluxed for 5 h, the solvent was removed in vacuo, resulting in 6.15 g A-benzyl-A-(2,3-dibromopropyl)-A-((4-methylphenyl)methyl)amine, in a crude yield of 100%. Pure compound can be obtained by column chromatography on silica gel using a mixture of hexane and EtOAc as an eluent. 

In addition to alkenes, imines are tremendously popular aziridine precursors via an aza-Darzens approach. For example, a stereoselective synthesis of C-sulfonylated aziridines was reported via an aza-Darzens approach employing bromomethyl phenyl sulfbne, NaHMDS, and a series of N-tert-butanesulfinyl imines (14MI969). Likewise as shown below, chiral tert-butane- and mesitylsulfinimines were subjected to an aza-Darzens reaction with substituted 2-bromoesters to provide a host of aziridines in good yield with excellent stereocontrol (14OL6920). In turn, these aziridines could be subsequently converted to chiral A/-H aziridines in a total of three steps starting with a wide range of commercially available aldehydes. 

This procedure can also be used for prepolymers possessing other reactive groups, such as mercapto, chloromethyl, bromomethyl epoxy, amino, aziridine, vinyl, carboxyl, hydroxy or alkoxymethyl groups. Oligomer emulsions can also be obtained by mixing water into the dissolved or liquid ionomer, because these products are inert with respect to water. 

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