Aziridines vinyl-, rearrangement

Aziridine, cis-7V-t-butyl-3-ethynyl-2-vinyl-rearrangement, 7, 540 Aziridine, 2-chlorocarbonyl-ring expansion, 7, 42 Aziridine, 2-chloromethyl-synthesis, 7, 42 Aziridine, Mcyanodiphenyl-irradiation, 7, 61 Aziridine, dihalo-reduction, 7, 74 thermolysis, 7, 73... 

Aziridine, 2,3-diphenyl-l-(2,4,6-trinitrophenyl)-irradiation, 7, 61 Aziridine, 1,2-divinyl-rearrangement, 7, 539 Aziridine, 2,3-divinyl-rearrangement, 7, 42, 65, 539 Aziridine, N-ethyl-inversion, 7, 6 Aziridine, 2-halo-reactions, 7, 74 Aziridine, A/-halo-invertomers, 7, 6 Aziridine, 2-methyl- N NMR, 7, 11 Aziridine, methylene-ring-ring valence isomerizations, 7, 22 synthesis, 7, 92 Aziridine, iV-nitroso-reactions, 7, 74 Aziridine, iV-phosphino-inversion, 7, 7 Aziridine, 1-phthalimido-UV irradiation, 7, 62-63 Aziridine, l-(3-thienyl)-2-vinyl-rearrangement, 4, 746 Aziridine, 7V-trimethylsilyl-inversion, 7, 7 Aziridine, 1,2,3-triphenyl-irradiation, 7, 61 Aziridine, vinyl-isomerization, S, 287 Aziridinecarboxylic acid ring expansion, 7, 262 Aziridine-2,2-dicarboxylic acid, 1-methoxy-diethyl ester... 

Ogawa et al. (12) used an intramolecular azide-alkene cycloaddition strategy to synthesize the oxygen-bridged aza[15]annulene 52 and the aza[15]annulene dicar-boxylate 55 (Scheme 9.12). 1,3-Dipolar cycloaddition of vinyl azide to the acrylate moiety followed by extrusion of nitrogen gave the aziridine 51. Rearrangement of 51 afforded the aza[15]annulene 52. The same approach was used to synthesize the aza[15]annulene 55. 

Important synthetic paths to azirines and aziridines involve bond reorganization, or internal addition, of vinylnitrenes. Indeed, the vinylnitrene-azirine equilibrium has been demonstrated in the case of trans-2-methyl-3-phenyl-l-azirine, which at 110 °C racemizes 2000 times faster than it rearranges to 2-methylindole (80CC1252). Created in the Neber rearrangement or by decomposition of vinyl azides, the nitrene can cyclize to the p -carbon to give azirines (Scheme 4 Section 5.04.4.1). 

Note that the first example bears out the stereochemical prediction made earlier. Only the two isomers shown were formed. In the second example, migration can > continue around the ring. Migrations of this kind are called circumambulatory rearrangements. Such migrations are known for cyclopentadiene, pyrrole, and phosphole derivatives.[1,5] Hydrogen shifts are also known with vinyl aziridines." ... 

Reaction of the quinone (12) with vinyl aziridine affords the dihydroazepinoquinone (14) in good yield <95TL4787>. The reaction proceeds via an aza-Claison rearrangement of the intermediate (13) followed by a sigmatropic rearrangement (Scheme 2). 

The loss of CO, S, SO, SO2, SO3, and N2 by thermolysis or photolysis has been used to make three- and four-membered rings for example, the cyclic sulfamidate 94 undergoes clean thermolysis at 70 C to form the vinyl aziridine 95 in excellent yield <2002T5979, CHEC-III(1.01.6.5)79> and Wolff rearrangement of diazo compounds 96 gives -lactams 97 (Scheme 51) <1973J(P1)2024>. 

Norbomene adds to photolytically produced ethoxycarbonylnitrene specifically at the exo face the same aziridine is produced in the thermal addition of ethoxycarbonyl azide, but via the triazoline rather than the nitrene, with much imine by-product. There can be problems of selectivity and rearrangements when one reacts ethoxycarbonylnitrene with more complex substrates, e.g. alkenic steroids. Ethoxycarbonylnitrene via a-elimination) adds to vinyl chlorides to give 2-chloroaziridines, which can be rearranged thermally to yield 2-chloroallyl carbamates. This nitrene also adds to enamines, giving an array of rearranged products. A modem discussion of the reactivities of ethoxycarbonylnitrene (electrophilic) in comparison with phthalimidonitrene (nucleophilic) towards alkenes of different electronic properties has tqipeared. ... 

The 4-isoxazoline ring includes an N-O bond connected to a rt-system (N-O-vinyl functionality) that shows a low thermochemical stability allowing ring-rearrangement reactions. Aziridines are generally assumed to be involved in... 

Sigmatropic rearrangements of cyclopropylimines <91TL7127> and cyclobutylimines <88H(27)1665> to generate fused bicyclic aziridines have been reported <84CHEC-I(7)47>. The sigmatropic rearrangement of isoxazoles to azirines will be covered in Section 1.01.9.6. Electrocyclic closure of vinyl-nitrenes to azirines will be discussed in Section 1.01.9.5. 

Ahman and Somfai constructed the indolizidine skeleton of (- )-525 by the novel and efficient base-induced aza-[2,3]-Wittig rearrangement of the vinyl-aziridine 581 (Scheme 76) (463,464). The product (98% yield) was the unsaturated... 

Preparation. - ZJ/recr Insertion. Ethoxycarbonylnitrene (EtOOCN ), generated by the EtaN-induced a-elimination of 4-N02C6H4S0aNHC00Et, adds to vinyl chlorides to give aziridines without appreciable contamination by insertion products, The reaction is stereospecific thus the addition to (244) gives (245), and the a-chloro-aziridines undergo facile rearrangements to alkenylamines, e.g (246). 

The factors that affect azepine formation versus production of open-chain rearranged compounds by cycloadditions to vinyl-aziridines (discussed in last years report) have been further assessed. The reaction of tetrahydronaphthalene tertiary alcohols with HNg-HgSC has been found to provide a high-yield regiospecific method for the synthesis of tetrahydro-2,3,4,5-benzo[b]-lH-azepines substituted at position 2... 

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