Biotransformations of fluorinated sulphenyl and sulphonyl compounds

Baker's‐Yeast‐Mediated Reduction of Sulfur‐Containing Compounds

“…The preparation of enantiomerically pure fluorine‐containing compounds by means of enzymatic or microbial systems has garnered much interest due to their potential use as drugs and valuable tools for metabolic studies. Yamazaki reported the yeast reduction of fluorinated β‐keto sulfides and found that the reduction of 1‐fluoro‐2‐oxopropyl phenyl sulfide ( 36 ) gave the alcohol ( R )‐ 37 with 70 % ee but with the opposite configuration to the corresponding non‐fluorinated sulfide,74 whereas Ghiringhelli75 and Moretti76 later reported baker's‐yeast‐mediated reduction of the p ‐tolyl sulfide derivative 38 to give the alcohol ( S )‐ 39 with >85 % ee . Interestingly, 1,1,1‐trifluoropropyl phenyl sulfide ( 40 ) did not undergo reduction (Scheme ) 74.…”

“…The fluorinated derivative 128 was reduced by baker's yeast to the corresponding alcohol 129 of S configuration with high enantioselectivity of >97 % ee 75 or >80 % ee 76 (Scheme ). However the reduction of 1‐chloro‐1,1‐difluoro‐3‐( p ‐tolylsulfonyl)propan‐2‐one ( 130 ) afforded the alcohol 131 with predominantly R configuration (78 % ee ) in 85 % yield 138…”

Regio- and stereoselective synthesis of vicinal fluorohydrins

“…Placing bulkier substituents close to the reaction centre, the enantioselectivity was significantly improved both for the anti-and the syn-compounds (Scheme 63) [53].…”