title: Development of an efficient, scalable, aldolase-catalyzed process for enantioselective synthesis of statin intermediates.
abstract: A process is reported for efficient, enantioselective production of key intermediates for the common chiral side chain of statin-type cholesterol-lowering drugs such as Lipitor (atorvastatin) and Crestor (rosuvastatin). The process features a one-pot tandem aldol reaction catalyzed by a deoxyribose-5-phosphate aldolase (DERA) to form a 6-carbon intermediate with installation of two stereogenic centers from 2-carbon starting materials. An improvement of almost 400-fold in volumetric productivity relative to the published enzymatic reaction conditions has been achieved, resulting in a commercially attractive process that has been run on up to a 100-g scale in a single batch at a rate of 30.6 g/liter per h. Catalyst load has been improved by 10-fold as well, from 20 to 2.0 wt % DERA. These improvements were achieved by a combination of discovery from environmental DNA of DERAs with improved activity and reaction optimization to overcome substrate inhibition. The two stereogenic centers are set by DERA with enantiomeric excess at >99.9% and diastereomeric excess at 96.6%. In addition, down-stream chemical steps have been developed to convert the enzymatic product efficiently to versatile intermediates applicable to preparation of atorvastatin and rosuvastatin.
authors.affiliation: Diversa Corporation, 4955 Directors Place, San Diego, CA 92121, USA. wgreenberg@diversa.com
authors.forename: William A
authors.initials: WA
authors.lastname: Greenberg
authors.forename: Alexander
authors.initials: A
authors.lastname: Varvak
authors.forename: Sarah R
authors.initials: SR
authors.lastname: Hanson
authors.forename: Kelvin
authors.initials: K
authors.lastname: Wong
authors.forename: Hongjun
authors.initials: H
authors.lastname: Huang
authors.forename: Pei
authors.initials: P
authors.lastname: Chen
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Burk
mesh_terms: D000595:Amino Acid Sequence; D000069059:Atorvastatin; D002384:Catalysis; D005464:Fluorobenzenes / Q000138:chemical synthesis*; D005634:Fructose-Bisphosphate Aldolase / Q000737:chemistry*; D006538:Heptanoic Acids / Q000138:chemical synthesis*; D008969:Molecular Sequence Data; D011743:Pyrimidines / Q000138:chemical synthesis*; D011758:Pyrroles / Q000138:chemical synthesis*; D000068718:Rosuvastatin Calcium; D013237:Stereoisomerism; D013449:Sulfonamides / Q000138:chemical synthesis*
chemical_list: D005464:Fluorobenzenes; D006538:Heptanoic Acids; D011743:Pyrimidines; D011758:Pyrroles; D013449:Sulfonamides; D000068718:Rosuvastatin Calcium; D000069059:Atorvastatin; D005634:Fructose-Bisphosphate Aldolase