[16853-85-3], LiAlH4, F.W. 37.95, m.p. >125° dec., d. 0.917, UN1410, EINECS 240-877-9, RTECS BD0100000, MDL MFCD00011075, TSCA Yes
Hazard Codes: H260-H314
Precautionary Codes: P231+P232-P264b-P280-P301+P330+P331-P303+P361+P353-P304+P340-P305+P351+P338-P310-P335+P334-P363-P370+P378r-P402+P404-P501c
Many procedures for reactions with this reagent which have been described in the literature are potentially unsafe on anything other than a very small scale, since often no precautions are given for mixing the reagent with flammable solvents. The following suggestions are offered for laboratory scale reductions:
Mixing with a flammable solvent must always be carried out under an inert atmosphere.
Reverse addition (solvent to reagent), if done rapidly, may be safer.
For THF, at least 10ml solvent per gram of reagent is recommended to absorb heat of mixing.
Efficient stirring is essential during mixing, reaction and workup.
The use of water or steam baths, or of electric heating mantles is to be strongly discouraged.
The reduction reaction should preferably be controlled by adjusting the rate of addition of the substrate rather than relying on external heating or cooling.
External heating or cooling, if required, should be by means of a suitable inert oil.
The use of Diethoxymethane, B23134 as a reaction solvent has also been recommended.
For phase-transfer reductions in hydrocarbon solvents, see 15-Crown-5, A12265. For formation of lithium tris(diethylamino)aluminum hydride and use in the reduction of esters or amides to aldehydes, see Diethylamine, A11716. For formation of a reagent for reduction of carboxylic acids to aldehydes, see 1-Methylpiperazine, A10837.
For reduction of sulfones, see Titanium(IV) chloride, 14713.
Monograph: J. Seyden-Penne, Reductions by the Alumino- and Borohydrides In Organic Synthesis, 2nd ed., Wiley, N.Y. (1997).
Hsu, C. P.; Jiang, D. H.; Lee, S. L.; Horng, J. L.; Ger, M. D.; Chang, J. K. Buckyball-, carbon nanotube-, graphite-, and graphene-enhanced dehydrogenation of lithium aluminum hydride. Chem. Commun. 2013, 49 (78), 8845-8847.
Gooodman, C. A.; Janci, E. M.; Onwodi, O.; Simpson, C. C.; Hamaker, C. G.; Hitchcock, S. R. A two-step, one pot preparation of amines via acyl succinimides. Synthesis of the calcimimetic agents cinacalcet, NPS R-467, and NPS. Tetrahedron Lett. 2015, 56 (30), 4468-4471.