Highly Diastereoselective Synthesis of 2,2-Disubstituted Cyclopentane-1,3-diols via Stepwise Ketone Reduction Enabling Concise Chirality Construction

Directed evolution of an alcohol dehydrogenase for the desymmetric reduction of 2,2-disubstituted cyclopenta-1,3-diones by enzymatic hydrogen transfer

Directed evolution of carbonyl reductase TbADH created mutant Tb2 with balanced activity toward ethyl secodione and isopropanol, enabling the desymmetric reduction of ethyl secodione to give (13R,17S)-ethyl secol with 94% yield, >99% ee and >99% de.

Engineering a carbonyl reductase for the scalable preparation of (S)-3-Cyclopentyl-3-hydroxypropanenitrile, the key building block of ruxolitinib

( S )- 3-Cyclopentyl-3-hydroxypropanenitrile is the key precursor for the synthesis of ruxolitinib. The bioreduction of 3-cyclopentyl-3-ketopropanenitrile ( 1a ) offers an attractive method to access this important compound. A carbonyl reductase (PhADH) from Paraburkholderia hospita catalyzed the reduction of 1a giving the ( S )-alcohol ( 1b ) with 85% ee. Rational engineering of PhADH resulted in a double mutant H93C/A139L, which enhanced the enantioselectivity from 85% to >98%, as well as a 6.3-fold improvement in the specific activity. The bioreduction of 1a was performed at 200 g/L (1.5 M) substrate concentration, leading to isolation of ( S )- 1b in 91% yield. Similarly, using this mutant enzyme 3-cyclohexyl-3-ketopropanenitrile ( 2a) and 3-phenyl-3-ketopropanenitrile ( 3a ) were reduced at high concentration affording the corresponding alcohols in >99% ee, and 90% and 92% yield, respectively. The results showed that the variant H93C/A139L was a powerful biocatalyst for reduction of β-substituted-β-ketonitriles.

Biosynthesis of chiral cyclic and heterocyclic alcohols via CO/C–H/C–O asymmetric reactions

This review covers the recent progress in various biological approaches applied to the synthesis of enantiomerically pure cyclic and heterocyclic alcohols through CO/C–H/C–O asymmetric reactions.