Functionalized chloroenamines in aminocyclopropane synthesis - XIV. Aminoannulated cyclopropanes - rigid building blocks for oligoamines

Wagemann, R.; Seibel, Jens; Vilsmaier, Elmar; Maas, Gerhard

doi:10.1016/s0040-4020(01)80789-4

Cited by 9 publications

(2 citation statements)

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“…6β-Configuration of both 12 and 13 followed from the hindrance of dynamics of one morpholine (ABXY system in the 1 H NMR ,,− ). 3α-Configuration of 12 could be deduced from the typical signals of the C(3)−H unit [ 1 H NMR (CDCl 3 ) δ = 3.02, 3 J AM = 3 J AN = 7.7 Hz; 13 C NMR (D 2 O) δ = 66.6 (d, 1 J CH = 142 Hz), (CDCl 3 ) δ = 67.2 (d); boat conformation ,,,, ]. The analogous signals of 13 indicated the presence of a 3β-configuration and a chair conformation [C(3)−H, 1 H NMR (CDCl 3 ) δ 3.09, 3 J AM = 10.7 Hz; 3 J AN = 7.9 Hz; 13 C NMR (D 2 O) δ 74.8 (d), 1 J CH = 134 Hz 1,2,12,16,17 ].…”

Section: Resultsmentioning

confidence: 99%

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A Strained Aminoazoniatricyclene Species: Result of an Intramolecular Stabilization of a Cyclopropaniminium Ion by an Amino Moiety

et al. 1996

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Ab initio calculations of the cationic intermediates of a cyclopropane-forming process of 1,4-diamino-6-chlorocyclohexene precursors predict the 3α-aminobicyclohexane-6-iminium ion 6c to be more stable than its 3β-isomer 7c. The latter, however, stabilizes itself by intramolecular cyclization leading to aminoazoniatricyclene species 9c. The aminocyclohexenyl cation 8c proved to have no minimum on both the MP2 and the MP4(SDTQ) potential energy surfaces. Optimization of species 8c causes a ring closure reaction to give iminium analogues 6c or 7c. The potential energy curve of this transformation 6c → 8c → 7c was calculated. Experimentally, solvolysis of chloro enamine isomers 4a and 5a was studied as a simple access to these cationic intermediates: 3α-amino 6-iminium ion 6a leading to 3α-amino 6-semiaminal 12 is generated exclusively from trans chloro enamine 4a and as main intermediate (67%) from cis chloro enamine 5a. In the latter case, aminoazonia compound 9a is formed as a byproduct (33%) which decomposes in water to give 3β-amino 6-semiaminal 13 via 3β-amino 6-iminium ion 7a. Aminoazoniatricyclene species 9a is obtained as stable tetrafluoroborate in acetonitrile or dichloromethane by reaction of chloro enamine isomers 4a or 5a with AgBF4 -. 1H and 13C NMR spectral and X-ray structural data are given for this strained tricyclic system 9a.

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Section: Resultsmentioning

confidence: 99%

“…3R-Configuration of 12 could be deduced from the typical signals of the C(3 12,16,17 ]. The analogous signals of 13 indicated the presence of a 3β-configuration and a chair conformation [C(3)-H, 1 H NMR (CDCl 3 ) δ 3.09, 3 J AM ) 10.7 Hz; 3 J AN ) 7.9 Hz; 13 C NMR (D 2 O) δ 74.8 (d), 1 J CH ) 134 Hz 1,2, 12,16,17 ].…”

Section: Resultsmentioning

confidence: 99%

A Strained Aminoazoniatricyclene Species: Result of an Intramolecular Stabilization of a Cyclopropaniminium Ion by an Amino Moiety

et al. 1996

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Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

2002

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Reductive amination is an important tool for synthetic organic chemists in the construction of carbon‐nitrogen bonds. This reaction, also termed reductive alkylation, involves condensation of an aldehyde or ketone with an amine in the presence of a reducing agent. A wide variety of substrates can be used including aliphatic and aromatic aldehydes and ketones, and even benzophenones. A range of amines from ammonia to aromatic amines, including those with electron‐withdrawing substituents, can be employed. For particularly sluggish reactions, such as those involving weakly electrophilic carbonyl groups, poorly nucleophilic amines, or sterically congested reactive centers, additives such as molecular sieves or Lewis acids are often useful. This chapter focuses on those conditions in which the carbonyl component, amine, and reducing reagent react in the same vessel. This review is restricted to reductive aminations using borohydride and borane reducing agents. This chapter concentrates on reductive amination chemistry mediated by borohydride and other boron‐containing reducing agents from 1971, the year when sodium cyanoborohydride was introduced, through the middle of 1999. In addition to reductive aminations of aldehyde and ketone substrates, reactions of related structures including acetals, aminals, ketals, carboxylic acids, nitriles, and dicarbonyls that form a nitrogen‐containing ring are reviewed. Intramolecular processes in which the substrate contains both the carbonyl and amine moieties are described. The intramolecular variant is a useful method for preparing cyclic amines. All of the various boron‐containing hydride sources in reductive aminations, including labeled metal hydrides, are reviewed. Instances of reductive aminations that failed are described. Applications of this method to a solid support in parallel synthesis in combinatorial chemistry as well as reductive aminations that proceed in tandem with a second reaction such as reductive lactamizations are discussed.

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ChemInform Abstract: Functionalized Chloroenamines in Aminocyclopropane Synthesis. Part 14. Aminoannulated Cyclopropanes ‐ Rigid Building Blocks for Oligoamines.

et al. 1994

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Functionalized Chloroenamines in Aminocyclopropane Synthesis. Part 14. Aminoannulated Cyclopropanes -Rigid Building Blocks for Oligoamines.-In continuation of a work concerning oligoamines with a rigid building block, the sterically pure (V) is prepared. Its diastereomers (VII) and (X) are synthesized as well. Structural properties of this new type of oligoamines are discussed. -(WAGEMANN, R.; SEIBEL, J.; VILSMAIER, E.; MAAS, G.; Tetrahedron 50 (1994) 3, 731-748;

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Functionalized chloroenamines in aminocyclopropane synthesis - XIV. Aminoannulated cyclopropanes - rigid building blocks for oligoamines

Cited by 9 publications

References 4 publications

A Strained Aminoazoniatricyclene Species: Result of an Intramolecular Stabilization of a Cyclopropaniminium Ion by an Amino Moiety

A Strained Aminoazoniatricyclene Species: Result of an Intramolecular Stabilization of a Cyclopropaniminium Ion by an Amino Moiety

Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

ChemInform Abstract: Functionalized Chloroenamines in Aminocyclopropane Synthesis. Part 14. Aminoannulated Cyclopropanes ‐ Rigid Building Blocks for Oligoamines.

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