Specific Solvent Issues / Safety Issues with Ketone Reduction

In general, solvent selection should follow the avoidance of any CMR solvents and in particular avoiding mixtures of hydride reagents in solvents where known incompatibilities exist:

Shimizu, S.; Osato,H.; Imamura, Y.; Satou, Y. Safety Evaluation of Sodium Borohydride in Dimethylacetamide. Org. Proc. Res. Dev. 2010, 14, 1518–1520.

Appropriate caution should be taken with hydride reagents that could generate H₂ and hence a flammable atmosphere during reaction or in a work-up quench procedure.

Isoni, V.; Mendoza, K.; Lim, E.; Teoh, S. K. Screwing NaBH₄ through a Barrel without a Bang: A Kneaded Alternative to Fed-Batch Carbonyl Reductions. Org. Proc. Res. Dev. 2017, 21, 992–1002.

Particular attention needs to be paid to the use of BH₃, BH₃ complexes or mixtures that could generate BH₃. Above certain concentrations, the highly flammable and explosive B₂H₆ can form in the headspace above reaction mixtures.
Supercritical and subcritical (gas-expanded liquids) have been used as greener media for the catalytic reduction of certain functional groups including ketones.

Hitzler, M. G.; Smail, F. R.; Ross, S. K.; Poliakoff, M. Selective Catalytic Hydrogenation of Organic Compounds in Supercritical Fluids as a Continuous Process. Org. Proc. Res. Dev. 1998, 2, 137–146.