Aluminum hydride reducing agents

Enantiomerically pure binaphthol is used as a chiral auxiliary. For example, it has been used to prepare chiral aluminum hydride reducing agents, chiral Lewis acids catalysts,8 and chiral crown ethers.9... 

Vitride . [Zeeland] Sodium bis(2-medioxyethoxy) aluminum hydride reducing agent... 

LAH LiAlH4 Lithium Aluminum Hydride. Reducing Agent. Explodes on contact with water —... 

For most laboratory scale reductions of aldehydes and ketones catalytic hydro genation has been replaced by methods based on metal hydride reducing agents The two most common reagents are sodium borohydride and lithium aluminum hydride... 

As in the preceding experiment, a lithium aluminum hydride-aluminum chloride reducing agent is prepared by the addition of 1.67 g (0.044 mole) of lithium aluminum hydride in 50 ml of anhydrous ether to 24.2 g (0.18 mole) of anhydrous aluminum chloride in 50-55 ml of anhydrous ether. 

Discovery. These catalysts were discovered during a study of the use of transition metal cyanides in combination with metal alkyl and hydride reducing agents in polymerizations. The combination of nickel cyanide and lithium aluminum hydride complexed very strongly with tetrahydrofuran. A similar complexing action occurred with propylene oxide and nickel hexacyanoferrate(II)-lithium aluminum hydride. This led to speculation as to the role of the double-metal cyanide itself. 

The third way to deliver the equivalent of two hydrogen atoms is to add hydride (H ) and a proton (H ). The most common hydride reducing agents contain a hydrogen atom bonded to boron or aluminum. Simple examples include sodium borohydride (NaBR,) and lithium aluminum hydride (L1AIH4). These reagents deliver H to a substrate, and then a proton is added from H2O or an alcohol. 

Successful MPV reduction of aliphatic P-aminoaldehydes to their corresponding y9-aminoalcohols was reported by Hayes and Drake (31). However, since the introduction of LiAIH4 in 1947 and the growth in usage of complex metal hydride reducing agents, aluminum alkoxides have fallen out of favor in organic synthesis. 

Sodium borohydride is a less powerful reducing agent than lithium aluminum hydride. Lithium aluminum hydride reduces acids, esters, aldehydes, and ketones, but sodium borohydride reduces only aldehydes and ketones ... 

Both sodium borohydride and lithium aluminum hydride reduce ketones or aldehydes to alkoxides, and hydrolysis gives the alcohol. Lithium aluminum hydride is a more powerful reducing agent than sodium borohydride. 

There are two common hydride reducing agents sodium borohydride (7 NaBH4) and lithium aluminum hydride (8 LiAlH4). Borohydride is an ate complex (see Chapter 6, Section 6.5.4, for definition of an ate complex) of BHg (7 is a tetrahydridoborate) and aluminum hydride is an ate complex of AlHg (8 is a tetrahydridoaluminate their respective lUPAC names are sodium tetrahydridoborate and lithium tetrahydridoaluminate. The borate anion is the Lewis acid-Lewis base complex of BHg (borane) and a hydride, whereas the alumi-nate anion is the Lewis acid-Lewis base complex of AlHg (aluminum hydride) and a hydride. Examination of the periodic table reveals that hydrogen is more... 

Both sodium borohydride and lithium aluminum hydride reduce ketones or aldehydes to alkoxides, and hydrolysis gives the alcohol. Lithium aluminum hydride is a more powerful reducing agent than sodium borohydride 2, 4, 6, 30, 31, 35, 36, 37, 39, 40, 44, 45, 46, 50, 59, 60. 

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