More Recent Developments Stoichiometric Copper Hydride Reagents

More Recent Developments Stoichiometric Copper Hydride Reagents 

Among its salient features, this copper hydride (written for simplicity from now on as the monomer (Ph3 P)CuH) can be prepared in multi-gram quantities from four precursor compounds (CuCl, NaO-t-Bu, PPh3, and H2) that are not only readily available but also very inexpensive (Eq. 5.5) [15]. It is also noteworthy that the byproducts of formation (NaCl and t-BuOH) are especially environmentally friendly . 

The quality of (Ph3P)CuH can vary, depending upon the care taken in the crystallization step. An unknown impurity - that shows broad signals at 3 7.78, 7.40, and 7.04 in the NMR spectrum in dry, degassed, benzene-de - is usually present in all batches of the reagent, although small amounts are not deleterious to its reduction chemistry. The hydride signal, a broad multiplet, occurs at 3.52 ppm (Fig. 5.1). Proton NMR data reported by Caulton on the related [(tol)3P]CuH include a broad but structured multiplet centered on d +3.50 in QDg [16]. 

Triphenylphosphine (100.3 g, 0.3825 mol) and copper(I) chloride (15.14 g, 0.1529 mol) were added to a dry, septum-capped 2 L Schlenk flask and placed under nitrogen. Benzene (distilled and deoxygenated, approximately 

The yields obtained by this procedure are roughly comparable to those obtained starting directly with purified (CuO-t-Bu)4 and one atmosphere of hydrogen, although higher yields (ca. 80%) have been reported under 1500 psi of hydrogen pressure [16]. 

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More Recent Developments Stoichiometric Copper Hydride Reagents 169... 

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