Acid-catalyzed hydrolysis and isotope exchange in lithium cyanotrihydroborate

Kreevoy, Maurice M.; Hutchins, J. E. C.

doi:10.1021/ja01043a077

Cited by 39 publications

(16 citation statements)

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“…The successful use of sodium cyanoborohydride is due to its stability in acidic solutions (down to pH$3). 20 Furthermore, reactions with sodium cyanoborohydride may be performed in any protic solvent including methanol. 2 The use of sodium triacetoxyborohydride rather than sodium cyanoborohydride eliminates the risk of residual cyanide in the final product.…”

Section: Resultsmentioning

confidence: 99%

Reductive N‐alkylation of secondary amines with [2‐¹¹C]acetone

Meij

Carruthers

Herscheid

et al. 2003

Labelled Comp Radiopharmac

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SummaryThe development of a labeling method for secondary amines with [2-11 C]acetone is described since the R 2 N-isopropyl moiety is present in many biologically active compounds. The influence of a variety of parameters (e.g. reagents, solvents, temperature, and time) on the reaction outcome is discussed. Under the optimal reaction conditions, [ 11 C]1-isopropyl-4-phenylpiperazine ([ 11 C]iPPP) was synthesized from [2-11 C]acetone and 1-phenylpiperazine in a decay-corrected radiochemical yield of 72%.

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Section: Resultsmentioning

confidence: 99%

Reductive N‐alkylation of secondary amines with [2‐¹¹C]acetone

Meij

Carruthers

Herscheid

et al. 2003

Labelled Comp Radiopharmac

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“…Similarly, BD 3 (Me 3 N) can be prepared by simple dissolution in 5 mol L -1 DCl for a controlled time [67]. In the case of complete hydrolysis of [BH 3 CN] -and BH 3 (NH 3 ) in D 2 O/D + , the main hydrogen isotopologue is D 2 , confirming that in these cases the hydrogen elimination reaction is much slower than the H-D exchange process [61,67].…”

Section: H-d Exchange In Borane Complexesmentioning

confidence: 86%

“…The initial step of the hydrolysis of CBH follows the same reaction pattern as that for [BH 4 [61] proposed protonation of boron to give an intermediate, BH 2 CN(H 2 ), the structure of which has been predicted to be similar to that of BH 3 (H 2 ) [79]. In this case, the following reactions have been proposed for the loss of the first hydrogen [61,79]:…”

Section: Hydrolysis Of [Bh 3 Cn] -mentioning

confidence: 86%

“…This is the case of [BH 3 CN] -and BH 3 (Me 3 N), the rate of hydrolysis of which is about 8 and 10 orders of magnitude lower than [BH 4 ] -( [61]. Similarly, BD 3 (Me 3 N) can be prepared by simple dissolution in 5 mol L -1 DCl for a controlled time [67].…”

Section: H-d Exchange In Borane Complexesmentioning

confidence: 98%

“…Little, sometimes controversial, information is available on the kinetics and the mechanism of hydrolysis of [BH 3 CN] -(CBH) which is known to be much more resistant to acid hydrolysis than [BH 4 ] - [61,66,78] (see Table 3). The initial step of the hydrolysis of CBH follows the same reaction pattern as that for [BH 4 [61] proposed protonation of boron to give an intermediate, BH 2 CN(H 2 ), the structure of which has been predicted to be similar to that of BH 3 (H 2 ) [79].…”

Section: Hydrolysis Of [Bh 3 Cn] -mentioning

confidence: 99%

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Mechanisms of chemical generation of volatile hydrides for trace element determination (IUPAC Technical Report)

D’Ulivo

Dědina

Mester

et al. 2011

Pure and Applied Chemistry

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Aqueous-phase chemical generation of volatile hydrides (CHG) by derivatization with borane complexes is one of the most powerful and widely employed methods for determination and speciation analysis of trace and ultratrace elements (viz. Ge, Sn, Pb, As, Sb, Bi, Se, Te, Hg, Cd, and, more recently, several transition and noble metals) when coupled with atomic and mass spectrometric detection techniques. Analytical CHG is still dominated by erroneous concepts, which have been disseminated and consolidated within the analytical scientific community over the course of many years. The overall approach to CHG has thus remained completely empirical, which hinders possibilities for further development. This report is focused on the rationalization and clarification of fundamental aspects related to CHG: (i) mechanism of hydrolysis of borane complexes; (ii) mechanism of hydrogen transfer from the borane complex to the analytical substrate; (iii) mechanisms through which the different chemical reaction conditions control the CHG process; and (iv) mechanism of action of chemical additives and foreign species. Enhanced comprehension of these different mechanisms and their mutual influence can be achieved in light of the present state of knowledge. This provides the tools to explain the reactivity of a CHG system and contributes to the clarification of several controversial aspects and the elimination of erroneous concepts in CHG.

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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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Acid-catalyzed hydrolysis and isotope exchange in lithium cyanotrihydroborate

Cited by 39 publications

References 0 publications

Reductive N‐alkylation of secondary amines with [2‐¹¹C]acetone

Reductive N‐alkylation of secondary amines with [2‐¹¹C]acetone

Mechanisms of chemical generation of volatile hydrides for trace element determination (IUPAC Technical Report)

Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

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Acid-catalyzed hydrolysis and isotope exchange in lithium cyanotrihydroborate

Cited by 39 publications

References 0 publications

Reductive N‐alkylation of secondary amines with [2‐11C]acetone

Reductive N‐alkylation of secondary amines with [2‐11C]acetone

Mechanisms of chemical generation of volatile hydrides for trace element determination (IUPAC Technical Report)

Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

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Reductive N‐alkylation of secondary amines with [2‐¹¹C]acetone

Reductive N‐alkylation of secondary amines with [2‐¹¹C]acetone