Borohydride derivatives

Unusual reducing properties can be obtained with borohydride derivatives formed in situ. A variety of reductions have been reported, including hydrogenolysis of carbonyls and alkylation of amines with sodium borohydride in carboxyHc acids such as acetic and trifluoroacetic (38), in which the acyloxyborohydride is the reducing agent. 

The Amine Complexes of Aluminium Hydride, V. Hydrido Aluminium Borohydride Derivatives. Inorg. Chem. 2, 515 (1963). 

Bornafix, 24 528 Borneols, 24 510, 527-528 Born—Haber cycle, 3 413 Born—Oppenheimer approximation, 16 736 Bornyl, 24 479 Borocarbides, 23 851 Borofluorides, 4 150 Borogypsum, 4 593 Borohydride derivatives, 13 614 Borohydride reduction effluent treatment, 9 432 34... 

Figure 7 Crystal structures of (a) uncomplexed [2.2.2]cryptand (12) (b) potassium complex of [2.2.2]cryptand (c) bis-borohydride derivative of [2.2.2]cryptand (reproduced with permission from 76JCS(P2)423 and 73AX(B)383)...

PBu 3 adducts. Reduction to undefined products was also noted for [Nbl4(py)2]515 and [NbX4(LL)], where LL= JV,JV,7V, 7V -tetramethyIethylenediamine.532 A poorly characterized borohydride derivative [Nb(BH4)2Cl2(MeCN)2] has been reported.533... 

Table 4 Regiochemistry of Ring Opening of Epoxides with Borohydride Derivatives...

The reactivity of U-H and U-C bonds in electron-poor tris(cyclopentadienyl)uranium complexes has been investigated. The compounds (C5H4PPh2-BH3)3UX (X = C1, Me) have been synthesized.81 The series of new tris(cylopentadienyl)uranium complexes also includes the borohydride derivatives Cp 3U(BH4) (Cp = Gp, C5H4PPh2, C5Me4PPh2-BH3, G5H4PPh2 BH3, C5Me4H, C5Me4PPh2).57 81... 

Alkyl groups are not the only substituents that can be attached to boron in order to generate new borohydride derivatives. Reaction of NaBH4 with HCN gives sodium cyanoborohydride (NaBH3CN), for example, a remarkably stable reagent that does not decompose in acid solution (the pH should be less acidic than pH 3). It is soluble in THF, MeOH, H2O, HMPA, DMF and sulfolane and is unreactive, making it very... 

A poorly characterized borohydride derivative [Nb(BH4)2Cl2(MeCN)2] has been reported. ... 

The half arrow notation is not restricted to M-H-M interactions, but applies equally well to other complexes that exhibit 3-center-2-electron bonds, such as those involving coordination of (i) G-H and B-H bonds, e.g. agostic alkyl complexes" and borohydride derivatives," and (ii) M-G bonds, e.g. symmetrically bridging methyl ligands. 

There are examples of UCP3X compounds where the ligand X makes use of more than one coordination site. One example is the borohydride derivatives synthesized according to eqs (12)-(14) (29). The compounds are exceedingly air and moisture sensitive. The cyanide... 

Sometimes, unactivated alcohols can be converted directly into amines. Denmark et al. were pursuing the synthesis of the structurally interesting fenestranes when they employed an intramolecular Mitsunobu reaction to form compound 106 in 87% yield as the borohydride derivative. ... 

Our intended synthesis of this compound began with the Diels-Alder condensation between butadiene and dimethyl itaconate. The less congested carboxyl group of the diester product can be hydrolyzed selectively and converted to the aldehyde via reduction of the acid chloride with a cuprous borohydride derivative. ... 

We disclosed a few years ago that borohydride derivatives of the rare earths can advantageously be used as precatalysts for the polymerization of nonpolar monomers, in combination with metal-alkyl compounds as cocatalysts [12], Such catalysts were found to be very versatile as various monomers were successfully tested. Magnesium cocatalysts gave rise to controlled polymerizations, and the results were different depending on the precatalyst/cocatalyst ratio. Aluminum cocatalysts required the addition of a borate activator to afford polymers. Other catalytic combinations starting from phenate and MOF (metal organic framework) derivatives of the rare earths were also assessed and compared with the borohydride-based ones. 

Multistage reactions can sometimes be avoided by prior attachment of a bridge to the affinant molecule. Using polyacrylamide-agarose as the initial matrix former. The coupled product was reduced with sodium borohydride. Derivative not certain. Not stated. - Presumably a non-covalent derivative. 

A new borohydride derivative soluble in benzene is the bis(cyclo-pentadienyOchlorotetrahydroboratozirconium compound (10). It has a reactivity similar to that of sodium borohydride and can thus be used to reduce non-polar... 

ALUMINUM, GALLIUM, INDIUM, AND THALLIUM Table 7. Aluminum-27 Chemical Shifts of AlH, AIR 275, and Borohydride Derivatives" ... 

The reduction of the complexes (7r-C5H5)MCl2, where M = Ti or Zr, with sodium borohydride gives the novel deep blue paramagnetic bridging borohydride derivative, 4.21 [245]. It is interesting that magnetic... 

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