Diaziridines iodine, reaction with

Diaziridines are also very strong oxidizing agents, even liberating chlorine from hydrochloric acid. The reaction with iodide in acidic solution proceeds almost quantitatively in most cases. The two equivalents of iodine obtained from a diaziridine (151) are of analytical value together with the number of acid equivalents consumed (B-67MI50800). 

The synthetic scheme often applied for the preparation of 3-aryl-3-(trifluoromethyl)-3//-diazirine nowadays is shown in Scheme 5a [60]. It starts by lithiation of an aryl bromide (38), which subsequently reacts with /V-ftrifluoroacetyl)piperidine 39 (easily prepared from trifluoroacetic anhydride and piperidine) under the formation of trifluoroacetophenone 40. Next, the ketone is converted into the corresponding oxime 41, after which the hydroxyl group is converted into its tosylate (42). Reaction with liquid ammonia (usually under pressure) allows the installment of the diaziridine group (43). Subsequent oxidation with iodine finally results in the diazirine (44). This five-step reaction sequence is especially compatible with acid-labile protective groups, which are often used to protect and/or install functionalities at the R position. 

The Schmitz reaction can be unsuccessful in sterically demanding environments in such circumstances, the electrophilic aminating agent reacts faster with ammonia than with hindered ketones <1965JA2665>. Consequently, the synthesis of 2-azi-camphane 64, a compound which is unobtainable under standard conditions <1996TL6647>, was achieved by slow diaziridination of camphor imine hydrochloride 63 (rather than camphor itself) with hydroxylamine-O-sulfonic acid (HOSA)-ammonia, followed by iodine-mediated oxidation (Scheme 22) <2001S379>. 

A similar method has been used to synthesize spirocyclic glycosyl diaziridines and diazirines (e.g., 66 and 67), which are used as glycosylidene carbene precursors. The diaziridine is made by reaction of the sulfonylated oxime 65 with ammonia, followed by oxidation to the diazirine with iodine (Scheme 23). 

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