art or by the processes disclosed in the present application the regioselective and stereoselective reduction of the compound of formula ii is carried out in the presence of ketoreductase enzyme and the reaction system further comprises a co factor a co factor regeneration system a substrate and dehydrogenase enzyme a buffer solution and an organic solvent u201c stereoselective or stereoselectivity u201d as used herein refers to the preferential formation in a chemical or enzymatic reaction of one stereoisomer over another stereoselectivity can be partial where the formation of one stereoisomer is favored over the other or it may be complete where only one stereoisomer is formed when the stereoisomers are enantiomers the stereoselectivity is referred to as enantioselectivity the fraction typically reported as a percentage of one enantiomer in the sum of both it is commonly reported in the art typically as a percentage as the enantiomeric excess calculated therefrom according to the formula major enantiomer minor enantiomer major enantiomer minor enantiomer where the stereoisomers are diastereoisomers the stereoselectivity is referred to as diastereoselectivity the fraction typically reported as a percentage of one diastereomer in the sum with others in the context of the present disclosure stereoselectivity refers to the fraction typically reported as a percentage of the 3 u03b2 hydroxy compound of formula i as opposed to the 3 u03b1 hydroxy compound of formula i u201c regioselective or regioselectivity u201d as used herein refers to the preference of one direction of chemical bond making or breaking over all other.