Cleavage of the carbon—nitrogen bond

White, Emil H.; Woodcock, D.

doi:10.1002/9780470771082.ch8

Cited by 12 publications

(10 citation statements)

References 272 publications

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“…Trialkylamine can be considered as the true alkylating agent because it has been shown that quaternary ammonium salts can be transformed into tertiary amines by cleavage of the carbon–nitrogen bond in an aqueous medium . Indeed, it was absolutely confirmed that the aromatic amine, aniline, reacted with tributylamine in the presence of a similar bifunctional tin–ruthenium catalyst to give 155 and 156 …”

Section: Borrowing Hydrogen Methodology In Homogeneous Catalysismentioning

confidence: 99%

Advances in One-Pot Synthesis through Borrowing Hydrogen Catalysis

2018

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The borrowing hydrogen (BH) principle, also called hydrogen auto-transfer, is a powerful approach which combines transfer hydrogenation (avoiding the direct use of molecular hydrogen) with one or more intermediate reactions to synthesize more complex molecules without the need for tedious separation or isolation processes. The strategy which usually relies on three steps, (i) dehydrogenation, (ii) intermediate reaction, and (iii) hydrogenation, is an excellent and well-recognized process from the synthetic, economic, and environmental point of view. In this context, the objective of the present review is to give a global overview on the topic starting from those contributions published prior to the emergence of the BH concept to the most recent and current research under the term of BH catalysis. Two main subareas of the topic (homogeneous and heterogeneous catalysis) have been identified, from which three subheadings based on the source of the electrophile (alkanes, alcohols, and amines) have been considered. Then the type of bond being formed (carbon-carbon and carbon heteroatom) has been taken into account to end-up with the intermediate reaction working in tandem with the metal-catalyzed hydrogenation/dehydrogenation step. The review has been completed with the more recent advances in asymmetric catalysis using the BH strategy.

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Section: Borrowing Hydrogen Methodology In Homogeneous Catalysismentioning

confidence: 99%

Advances in One-Pot Synthesis through Borrowing Hydrogen Catalysis

2018

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“…At appropriate intervals of time, aliquots were removed and analyzed carefiilly for residual hydride by hydrolysis, and the hydride utilized per equivalent of olefin was calculated. 3 The disappearance of the olefinic proton signal was monitored by XH NMR integration when the solvent was CCl* X1B NMR spectra were studied in many cases in order to gain some information on the boron species in the hydroboration mixture. When the reaction was complete, the hydroboration mixture was oxidized with H202 and NaOH.…”

mentioning

confidence: 99%

Hydroboration. 57. Hydroboration with 9-borabicyclo[3.3.1]nonane of alkenes containing representative functional groups

Brown¹,

Chen²

1981

J. Org. Chem.

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The hydroboration of alkenes containing representative functional groups was examined with 9-borabicyclo[3.3.1]nonane (9-BBN) in order to extend the hydroboration reaction for the preparation of functionally substituted organoboranes. Terminal alkenes containing a remote functional group are hydroborated with a remarkable regioselectivity (>98% terminal), producing the corresponding stable organoboranes. 9-BBN hydroborates the allylic derivatives so as to place boron essentially on the terminal carbon atom (>97%). The directive effect is further enhanced (>99%) in the case of jS-methylallyl derivatives. The hydroboration of crotyl derivatives attaches boron predominantly at the 2-position, followed by an elimination-rehydroboration sequence.However, crotyl alcohol can be protected against elimination as the tert-butyl or tetrahydropyranyl ethers. The hydroboration-oxidation of ethyl crotonate involves a series of elimination, hydroboration, and condensation processes. In the vinyl, crotyl, and isobutenyl systems, the mesomeric effect of the substituent favors the placement of boron at the ^-position, while the inductive effect favors the «-position, with the former effect predominating in most cases. Acyclic ß-substituted organoboranes undergo rapid elimination. Nonpolar solvents and lower reaction temperatures decrease the rate of elimination. However, those derived from cyclic vinyl derivatives are relatively stable under neutral conditions, undergoing facile elimination in the presence of a base.

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“…1973, 7, 295. (4) Kessler, H. Tetrahedron 1974, 30, 1861. (5) McCarty, C. G. "The Chemistry of the Carbon-Nitrogen Double…”

mentioning

confidence: 99%

Mechanism of an acid-catalyzed geometric isomerization about a carbon-nitrogen double bond

Johnson¹,

Silk²,

Nalley³

et al. 1981

J. Org. Chem.

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Reaction of sec-Butyllithium with Triene 1. This reaction was carried out in similar fashion to those using n-butyllithium and ieri-butyllithium. Thus sec-butyllithium (2.3 mL, 4.08 M, 9.48 mmol) in cyclopentane was reacted at 0 °C for 30 min with a solution of triene 1 (1.52 g, 8.02 mmol) in 3 g of dry THE. Quenching with degassed water and separation of products by gas chromatography gave 0.31 g of triene 1 (20.6%), 0.56 g of 5c (37%), 0.4 g of 6c (26.2%), and 0.25 g of 4c (16.2%). Crude samples were purified by high-pressure LC (see above). NMR spectra are summarized in Table I. Mass spectral data: 4c, m/e

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Cleavage of the carbon—nitrogen bond

Cited by 12 publications

References 272 publications

Advances in One-Pot Synthesis through Borrowing Hydrogen Catalysis

Advances in One-Pot Synthesis through Borrowing Hydrogen Catalysis

Hydroboration. 57. Hydroboration with 9-borabicyclo[3.3.1]nonane of alkenes containing representative functional groups

Mechanism of an acid-catalyzed geometric isomerization about a carbon-nitrogen double bond

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