CHOW. Can. J. Chem. 53,3014(1975).Two novel rearrangements of nitroso alkanes, one intramolecular acid catalyzed cleavage reaction and the other ring enlargement during hydride reduction, are described. Aminium radical initiated addition to norbornene under nitrogen gave cis-exo-and trans-2-nitroso-3ammonium norbornanes in a good yield. Whereas the trans isomer underwent the usual nitroso group reactions, i.e., tautomerization, dimerization, and HNO addition, the cis-exo isomer and its hydroxy analog cleaved extremely readily to give 1,3-bisformylcyclopentane derivatives. The stereoelectronic driving force in this cleavage is interpreted as the intramolecular proton transfer and the electron reorganization via a cyclic transition state. Metal hydride reduction of the trans isomer was accompanied by ejection of the neighboring amino group and an expansion of the ring to form an azabicyclic compound. A sequence involving an intramolecular displacement to form aziridine followed by the reductive cleavage is proposed. K. SOMOSEKHAREN PILLAY, SHI C. CHEN, THOMAS MOJELSKY et YUAN L. CHOW. Can. J. Chem. 53,3014 (1975). On decrit deux nouveaux rearrangements des nitroso alkanes: une reaction de coupure intramolCculaire catalyske par les acides et une autre impliquant une expansion de cycle au cours d'une reduction par les hydrures. L'addition au norbornene initiee par le radical amminium, se fait sous atmosphere d'azote et conduit, avec de bons rendements, aux cis-exo-et trans-nitroso-2 ammonium-3 norbornanes. Alors que le groupe nitroso de I'isomkre trans reagit normalement, a savoir tautomerisation, dimkisation et addition de HNO, l'isomtre cis-exo et son analogue hydroxyle se coupent extrtmement facilement pour conduire aux derives bisformyl-1,3'cyclopentanes. On suggere que la force stCreotlectronique aidant cette rupture est le transfert intramolCculaire d'un proton et la reorganisation electronique par I'intermediaire d'un Ctat de transition cyclique. La reduction de I'isomtre trans par les hydrures complexes est accompagnee par une expulsion du groupe amino voisin et par une expansion de cycle conduisant a un compost azabicyclique. On propose un mecanisme impliquant un deplacement intramoleculaire conduisant a une aziridine qui serait ensuite coupee lors de la reduction. [Traduit par le journal] 5 -9 5 R,, R, = CH(OCH,), 6 R, = CHO; R, = CH(OCH,), 7 R, = CH(OCH,),; R, = CH=NOH 8 R,, R, = CHO 9 R, = CHO; R, = CH=NOH

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Under basic conditions 2-aminocycloalkyl nitrate esters undergo amino-group-assisted cleavage of the C(l)-C(2) bond to give dialdehydes. PHOTOADDITION of N-nitrosopiperidine (NNP) or N-nitrosodimethylamine (NND) to cyclohexene under acidic conditions in the presence of oxygen yields a mixture of the hydrochlorides of cis-and trans-2-amino-nitrate esters.1 The nitrate group is known to undergo G O as well as 0-N bond scissions.a In aqueous solutions, the nitrates (1) are stable a t pH 1, but they gradually undergo solvolysis and elimination at pH 8-9 to form cis-and trans-2-aminocyclohexanols and 2-aminocyclohexanones.1 A careful g.c.-m.s. analysis of the decomposition products shows that ca. 10% of dialdehyde (2) is also formed. Obviously the dialdehyde is derived from the cleavage of the C(l)-C(2) bond assisted by the lone-pair electrons of the amine group as shown in (1) (Scheme 1). This new mode of nitrate decomposition can become the major pathway depending on the structure of 2-amino-nitrate esters.r. bNMe2,CHO

K. SOMOSEKHAREN PILLAY, KAORU HANAYA, and YUAN L. CHOW. Can. J. Chem. 53, 3022 (1975).Oxidative photoaddition of nitrosamines to norbornene gave both cis-exo-and trans-2nitrato-3-aminonorbornanes that were stable in their protonated form under photolysis wnditions. The free bases underwent a novel cleavage reaction assisted by the lone pair of the amino group to give 1,3-bis(formy1)cyclopentane. In addition these nitrates also underwent solvolysis to give cis-exo-2-hydroxy-3-aminonorbornane. The mechanisms of these basic decompositions are discussed.K. SOMOSEKHAREN PILLAY, KAORU HANAYA et YUAN L. CHOW. Can. J. Chem. 53, 3022 (1975).La photoaddition oxydative des nitrosamines au norbornitne conduit aux cis-exo-et transnitrato-2 amino-3 norbornanes; dans les conditions de la photolyse, ces deux isomitres sont stables sous leur forme protonke. Les bases libres subissent une nouvelle rkaction de fission aid& par le doublet libre du groupe amino et fournissent le bis(formyl)l.3 cyclopentane. De plus ces nitrates subissent une solvolyse pour conduire aux cis-exo-hydroxy-2 amino-3 norbornane. On discute des mkanismes de ces dkompositions en milieu basique.[Traduit par le journal1 'For Part XXXI, see ref. 1. Part of the report was published in the preliminary communication (see ref. 2). of 3-exo-piperidino-endo-bicyclo[2.2.1]heptan-2-ZOn sabbatical leave from Yamagata University, 01 (7, R2 = -(CH2)5-)Was isolated as the Yamagata, Japan, 1973-1974 hydrochloride salt. To avoid the decomposition Can. J. Chem. Downloaded from www.nrcresearchpress.com by KAIYOKENKYU KAIHATSU KIKO on 11/20/14For personal use only.

In HCl‐haltiger methanolischer Lösung addiert Norbornen (I) unter UV‐Bestrahlung das Nitrosamin (II) zum intermediären trans‐Addukt (III) sowie seinem cis‐exo‐Isomeren.