Nitrones cycloaddition to 1-vinyl-4,5-dihydro-1Н-benzo[g]indole proceeds regio-and steroselectively affording a single diastereomer of 5-(hetaryl-substituted)isoxazolidine.The reaction of nitrones with alkenes and alkynes proceeds with a high stereoselectivity to give isoxazolidines and isoxazolines, precursors of analogs of naturally occurring compounds possessing a biologic action, like β-lactam antibiotics and alkaloids [1][2][3][4]. Pyrrole and its derivatives also are important structural fragments of various natural compounds, e.g., chlorophyll, porphyrins, vitamin В 12 , and a number of others [5]. Lately efficient procedures were developed for the synthesis of compounds containing ensembles of pyrrole and imidazole [6], tetrahydroindole and triazole [7], pyrrole and isoxazolidine rings [8].We report here on the study of the process occurring between 1-vinyl-4,5-dihydro-1Н-benzo[g]-indole 1, easily obtained by Trofimov reaction [9][10][11], and nitrones of diverse structures: aldonitrones, C,Ndiaryl-(2a and 2b); N-aryl-С-carbamoylnitrones (2c and 2d), and ketonitrones, N-aryl-С,С-bis-(methoxycarbonyl)nitrones (2e and 2f). The heating for 4-19 h in toluene at 110°С furnished with a high regio-and stereoselectivity an adduct of 1,3-dipolar cycloadditon of nitrones to the vinyl group of indole 3a-3f. The structure of compounds obtained was established from the spectral data: The 1 Н NMR spectrum of compound 3a contained signals from the protons attached to atoms С 3 and С 5 of the isoxazolidine ring as doublets of doublets at 4.86 and 6.60 ppm respectively, and also the signals of protons in the position 4 at 2.93 (d.d.d) and 3.38 (d.d.d) ppm.The regioselectivity of nitrones addition to the vinyl group is in agreement both with the polarization of the nitrone (by the negatively charged oxygen atom) and the polarization of the vinyl group caused by the electron-excessive pyrrole ring. The cycloaddition is characterized by a high stereoselectivity as seen from the formation of a single stereoisomer where the substituents at the atoms С 3 and С 5 are located in the cis-position. The cis-orientation of the substituents at the atoms С 3 and С 5 of the isoxazolidine ring in R 1 = R 2 = Ph, R 3 = H (a); R 1 = Ph, R 2 = 4-BrC 6 H 4 , R 3 = H (b); R 1 = Ph, R 2 = C(O)NHPh, R 3 = H (c); R 1 = Ph, R 2 = C(O)NH(p-Tol), R 3 = H (d); R 1 = Ph, R 2 = R 3 = COOMe (e); R 1 = 4-ClC 6 H 4 , R 2 = R 3 = COOMe (f). N N R 2 O R 1 toluene 110 o C N O N R 1 R 2 + R 3 R 3 1 2a _ 2f 3a _ 3f _ +