Hydroxynitrile lyases (HNLs) or oxynitrilases (EC 4.1.2.10) catalyse the synthesis of cyanohydrins from aldehydes or reactive ketones (see Reaction Scheme and Examples). Cyanohydrins are important precursors for a wide-variety of chiral building blocks such as amino alcohols, hydroxyl acids, etc. (see References).

Reaction Scheme and Examples:

Selected References:

1. Sharma, M.; Sharma, N.; Bhalla, T.   “Hydroxynitrile  lyases: At the interface of biology and chemistry”,   Enzyme and Microbial Technology, 2005,  37,  279-294.

2. Gruber-Khadjawi, M.; Purkarthofer, T.; Skranc, W.; Griengl, H. “Hydroxynitrile lyase-catalyzed enzymatic nitroaldol (Henry) reaction”, Advanced Synthesis & Catalysis, 2007, 349, 1445-1450. 

3. Chen, P.; Han, S.; Lin, G.; Li, Z.   “A Practical High Through-Put Continuous Process for the Synthesis of Chiral Cyanohydrins”,   Journal of Organic Chemistry, 2002, 67, 8251-8253.