Diazirines 3-trifluoromethyl-3-aryl

Table 4 Photoreactive Peptides Modified with 4-[3-(Trifluoromethyl)-3//-diazirin-3-yl]aryl-Based...

Scheme 5 Preparation and examples of diazirines. (a) Synthetic scheme for preparation of 3-aryl-3-(trifluoromethyl)-3//-diazirines. (b) Examples of diazirine functionalized compounds...

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. 

Hashimoto, M., Kanaoka, Y. Hatanaka, Y. (1997). A versatile approach for functionalization of 3-aryl-3-(trifluoromethyl)diazirine photophores. Heterocycles, 46,119-122. 

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