ISSN 1070-4280, Russian Journal of Organic Chemistry, 2012, Vol. 48, No. 12, pp. 1530–1535. © Pleiades Publishing, Ltd., 2012. Original Russian Text © M.Yu. Moskalik, V.V. Astakhova, B.A. Shainyan, 2012, published in Zhurnal Organicheskoi Khimii, 2012, Vol. 48, No. 12, pp. 1559–1564. 1530 Oxidative Addition of Trifluoromethanesulfonamide to Cycloalkadienes M. Yu. Moskalik, V. V. Astakhova, and B. A. Shainyan Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, ul. Favorskogo 1, Irkutsk, 664033 Russia e-mail: moskalik@irioch.irk.ru Received April 17, 2012 Abstract—Reactions of trifluoromethanesulfonamide with cyclopentadiene, cyclohexa-1,3- and -1,4-dienes, cyclohepta-1,3,5-triene, and cycloocta-1,3-diene in the presence of t-BuOCl–NaI were studied. Trifluoro- methanesulfonamide added at one double bond of cyclopentadiene and cyclohexa-1,3-diene in regio- and stereoselective fashion to give N-(5-iodocyclopent-2-en-1-yl)trifluoromethanesulfonamide and trans-N,N′-cy- clohex-3-ene-1,2-diylbis(1,1,1-trifluoromethanesulfonamide), respectively. The reaction with cyclohexa-1,4- diene involved both isolated double bonds to produce N,N′-(2-chloro-5-iodocyclohexane-1,4-diyl)bis(1,1,1-tri- fluoromethanesulfonamide) which underwent halophilic reduction of the CHI group by the action of NaI and elimination of HCl, leading to N,N′-(cyclohex-2-ene-1,4-diyl)bis(1,1,1-trifluoromethanesulfonamide). Under analogous conditions, cyclohepta-1,3,5-triene was oxidized to benzaldehyde, while no reaction with trifluoro- methanesulfonamide occurred. In continuation of our studies on reactions of tri- fluoromethanesulfonamide (I) with compounds having one or two C=C bonds under oxidative conditions [1, 2], in the present work we examined its reactions with cyclopentadiene (II), cyclohexa-1,3-diene (III), cyclohexa-1,4-diene (IV), cyclohepta-1,3,5-triene (V), and cycloocta-1,3-diene ( VI ) in the presence of t-BuOCl–NaI · 2 H 2 O. There are no published data on reactions of dienes with sulfonamides in oxidative sys- tems where generation of sulfonylnitrenes is possible; an exception is our recent publication on the formation of 9-heterobicyclo[4.2.1]nonanes in the reaction of trifluoromethanesulfonamide with cycloocta-1,5-diene [2]. On the other hand, open-chain and cyclic 1,3-di- enes are known to react with N-(phenyl-λ 3 -iodanyli- dene)-4-toluenesulfonamide TsN=IPh as source of tosylnitrene, yielding aziridines as a result of addition at only one double bond of the diene [3, 4]. Two examples of 1,4-addition of sulfonylnitrenes to dienes were described, namely the reaction of TsN=IPh with cycloocta-1,3-diene leading to 9-tosyl-9-azabicyclo- [4.2.1]non-7-ene [3] and the reaction of RN=IPh (R = Ts, Ns) with open-chain dienes and cycloocta-1,3- diene in the presence of Cu(hfacac) 2 , which afforded 2,5-dihydropyrroles [5]. The latter process may be regarded as [1 + 4]-cycloaddition only formally, taking into account that 2-vinylaziridines are formed below 36°C and that they undergo isomerization to 2,5-dihy- dropyrroles as the temperature further rises to 100°C [5] (Scheme 1). Furthermore, cycloocta-1,3-diene reacts with RN=IPh at 100°C to give vinylaziridines which undergo rearrangement into 9-azabicyclo[4.2.1]non-7- DOI: 10.1134/S1070428012120068 Scheme 1. Cu(hfacac) 2 PhMe, 25–36°C N R 3 Ts R 2 R 4 R 1 100°C N Ts R 2 R 1 R 4 R 3 R 3 R 1 R 2 R 4 + TsN=IPh R 1 , R 2 , R 3 , R 4 = H, Me, Ph, Bzl. R = Ts, Ns. + RN=IPh Cu(hfacac) 2 PhMe, 150°C N R Scheme 2.