Thermal [2 + 3] cycloaddition of N-trichloroacetyldiphenylcyclopropenimine to 3-aroylaziridines and 3-carbomethoxyaziridines

Abstract

N-Trichloroacetyldiphenylcyclopropenimine reacted with either cis-or trarzs-3-benzoyl-1-cyclohexyl-2-m-nitrophenylaziridine in a [2+ 31 cycloaddition to the C=N bond of the imine to form (a) 5-benzoyl-2-m-nitrophenyl-4-(spirodiphenylcyclopropene)-3-(trichloroacetylhydrate)-imidazolidine and (b) l-cyclohexyl-4-(cis-1,2-diphenylvinyl)-3-dichloroacetyl-2-n-nitrophenylimidazoline. Similar reactions with other 3-aroylaziridines gave analogous irnidazolidines and imidazolines. Isolation of an unhydrated imidazolidine of type (a) in the corresponding addition with 3-carbomethoxy-1-cyclohexyl-2-phenylaziridine gave direct spectroscopic proof for the cyclopropene moiety in these adducts. The orientation of the 1,3 dipolar additions was confirmed by a reaction using a specifically 3-deuterated aziridine.The isolation of these adducts of type (a) strongly supports the previously suggested intermediacy of an oxazolidine in the analogous addition of 3-aroylaziridines to diphenylcyclopropenone.

1,3-Dipolar cycloaddition of nitrosonaphthols to 3-aroylazindines. Novel syntheses of substituted naphtho[1,2-d]oxazoles and naphtho[2,1-d]oxazoles

“…Since 1 and 2 are obtained in approximately equal yields it is clear that the steric influence on orientation in the reactions with 1-nitroso-2-naphthol is negligible. A similar conclusion has very recently been reached by Kresze et al in a study of the Diels-Alder additions of nitrosobenzene to substituted dienes (33)-In contrast, the 1,3-dipolar cycloadditions of 3-aroylaziridines to dipolarophiles containing heteromultiple bonds all took place exclusively in one orientation presumably due to more stringent steric control, for example in addition to the C=S bond in aryl isothiocyanates (15), the C=N bond in imines and sulfonylimines (16) and iminocyclopropenes (20), and the C=O bond in aryl aldehydes, chloral (19), and diphenylcyclopropenone (17,18).…”

“…We have reported the additions of 3-aroylaziridines and 3-carboalkoxyaziridines to the following heteromultiple bonds as dipolarophiles, (i) the C=S bond of aryl isothiocyanates with the formation of 4-aroyl-5-arylamino-4-thiazolines (15), (ii) the C=N bond of imines and sulfonylimines with the formation of imidazolidines (16), (iii) the C=O bond of diphenylcyclopropenone which ultimately affords 4-aroyl-4-oxazolines (17,18), (iv) the C=O bond of aryl aldehydes and chloral to form oxazolidines (19), and (v) the C=N bond of cyclopropenimines to form imidazolines and imidazolidines (20).…”