Chemistry of oxaziridines. 18. Synthesis and enantioselective oxidations of the [(8,8-dihalocamphoryl)sulfonyl]oxaziridines

Enantioselective Synthesis of α-Hydroxy Ketones via Benzaldehyde Lyase-Catalyzed C−C Bond Formation Reaction

“…This was repeated every 24 h. After 96 h the conversion was determined as 97% (GC-MS). Work-up according to the former procedure afforded (R)-2-HPP as a viscous oil; yield: 285 mg (94%, > 99% ee); 96% ee; Lit [35]. [a] 20 D : À 80.9 (c 2.0, CHCl 3 ) for > 95% ee (S)]; HPLC (Chiralpak AD, isohexane/2-propanol 90:10, flow 0.80 mL min À1 , 20 8C): R t (S) 12.1 min; R t (R) 14.3 min; AD, isohexane/2-propanol 90:10, flow 0.80 mL min À1 , 208C): R t (S) 9.7 min; R t (R) 11.1 min; 1 H NMR (400 MHz, CDCl 3 /CCl 4 ): d 7.81 ± 7.90 (m, 1H), 7.56 ± 7.67 (m, 1H), 7.12 ± 7.31 (m, 2H), 4.96 (q, J 6.8 Hz, 1H), 3.72 (br.s, 1H), 1.29 (d, J 6.8 Hz, 3H); 13 C NMR (100 MHz, CDCl 3 /CCl 4 ): d 198.2, 163.8 (d, J 251 Hz), 134.5 (d, J 12 Hz), 131.3, 129.9, 124.5, 115.9 (d, J 23 Hz), 72.2, 21.1.…”

Enantioselective electrochemical oxidation of enol acetates using a chiral supporting electrolyte

“…Comparison of chiral liquid chromatographic behaviors of the enantiomeric mixture of ␣-acetoxypropiophenone (4a) obtained from the anodic oxidation with those of authentic (S)-␣-acetoxypropiophenone 26 indicated that the (R)-enantiomers were preferentially obtained in the present anodic oxidation of 1-acetoxystyrene derivatives (3).…”

The small molecule tool (S)-(−)-blebbistatin: novel insights of relevance to myosin inhibitor design

“…† An interesting variation in the degree of asymmetric induction in the quinolone hydroxylation reaction was also observed as a function of structure, although in all cases the absolute configuration of the resulting analogue was the same [(S)-(-)]. Quinolones 15-17 all reacted with (-)-[ (8,8-dichlorocamphoryl)sulfonyl]oxaziridine (18) 11 under optimised conditions to give the desired analogues 5-7 respectively in good yield and high enantiomeric excess (ee 86-90%) in line with our report 9 on the synthesis of 1 (Scheme 1, column 8). As expected, 9 the ee of the asymmetric hydroxylation reaction for these substrates was reduced significantly when the dihydro-oxaziridine 19 was used instead of 18 (Scheme 1, column 9).…”