Abstract
Ketones and aldehydes are conveniently and rapidly reduced to the corresponding alcohols in good yields using sodium borohydride under sealed-tube microwave conditions in either 95% ethanol or water. In purely aqueous systems, highly aliphatic substrates are sluggish, but this can be overcome by introducing sodium dodecyl sulfate (SDS) at the critical micelle concentration. With a 2:1 substrate/borohydride ratio and a reaction temperature of 100 °C, reduction is typically complete within 1 min in 95% ethanol and 5 min in water/SDS. The methodology is well suited for parallel and combinatorial synthetic approaches.
GRAPHICAL ABSTRACT
ACKNOWLEDGMENTS
The authors gratefully acknowledge Allegheny College and the National Science Foundation (CCLI 0837640) for generous support of this project.
Notes
a Molar ratios of substrate/borohydride are 2:1 for 95% ethanol and 3:2 for aqueous systems.
b Calculated using ACD/Labs Software v11.02 via SciFinder.
c 94% after 5 min.
d 94% after 30 min.
e 98% after 5 min.
f 92% after 5 min in tetrahydrofuran.