Interaction of Diborane with Silyl Cyanides¹

Quantifizierung der Reduktiven Aminierung in Nichtenzymatischer Aminosäuresynthese

“…Die NMR‐spektroskopische Analyse der Reaktion von Pyruvat ( K1 ) mit stöchiometrischem NaBH 3 CN in wässriger Phosphatlösung (0.5 M, pH 5) zeigte die Bildung von 71 % Laktat, Wasserstoffgas, Borsäure, 25 % Cyanhydrin und 4 % nicht umgesetztem K1 nach einer Reaktionszeit von 18 h (Schema 2). [21–23] Die Bildung des Cyanhydrins erwies sich als reversibel, und folglich stellten wir fest, dass die Laktatkonzentration über Tage langsam weiter anstieg. Bei pH 4 hingegen war die Cyanhydrinbildung mit K1 vernachlässigbar gering, weshalb unsere nachfolgend diskutierten kinetischen Untersuchungen großteils bei pH 4 durchgeführt wurden.…”

Quantification of the hydride donor abilities of NADH, NADPH, and BH3CN−in water

“…Thermochemical methods have been extensively applied to compare the hydride donor strength of various NADH analogues, typically in acetonitrile solutions. 3,6 However, due to the instability of BH 2 CN, 7 the oxidation product of BH 3 CN − , equilibrium studies are hampered. The only tentative thermochemical comparison of the hydride donor strength of BH 3 CN − with NADPH thus comes from quantum-chemically calculated enthalpic hydricities considering acetonitrile solvation by an implicit solvation model (Δ H H− (NADPH) = 77.1 kcal mol −1 , Δ H H− (BH 3 CN − ) = 75.3 kcal mol −1 ).…”

“…S4-S7 †). 7 Having established the identity of the reactions of E with both hydride donors, kinetic studies were next performed. Nucleophilicity parameters were determined using a consistent set of amino-substituted benzhydrylium ions E as reference electrophiles (Fig.…”

Preparation of cyanoformates. Crown ether phase transfer catalysis

“…An alternative preparation of tert-butyl cyanoformate involves several steps.9 Recently, trimethylsilyl cyanide has been shown to react with methyl and ethyl chloroformates to yield the corresponding cyanoformates.14 However, a drawback to this latter procedure is the necessity to prepare trimethylsilyl cyanide. [15][16][17] We should like to report that cyanoformates can be prepared in good to excellent yields by the The reaction is also related to the preparation of benzoyl cyanides by reaction of benzoyl chlorides with cyanide ion under PTC conditions. 22 The preparation of cyanoformates is a cleaner reaction, since no formation of dimers which was a major side reaction in the preparation of benzoyl cyanides under PTC conditions was observed to occur.…”