Subtilisin-Catalyzed Resolution of <i>N</i>-Acyl Arylsulfinamides
作者:Christopher K. Savile、Vladimir P. Magloire、Romas J. Kazlauskas
DOI:10.1021/ja045397b
日期:2005.2.1
We report the first biocatalytic route to sulfinamides (R-S(O)-NH2), whose sulfur stereocenter makes them important chiral auxiliaries for the asymmetric synthesis of amines. Subtilisin E did not catalyze hydrolysis of N-acetyl or N-butanoyl arylsulfinamides, but did catalyze a highly enantioselective (E > 150 favoring the (R)-enantiomer) hydrolysis of N-chloroacetyl and N-clihydrocinnamoyl arylsulfinamides. Gram-scale resolutions using subtilisin E overexpressed in Bacillus subtilis yielded, after recrystallization, three synthetically useful auxiliaries: (R)-p-toluenesulfinamide (42% yield, 95% ee), (R)-p-chlorobenzenesulfinamide (30% yield, 97% ee), and (R)-2,4,6-trimethylbenzenesulfinamide (30% yield, 99% ee). Molecular modeling suggests that the N-chloroacetyl and N-dihydrocinnamoyl groups mimic a phenylalanine moiety and thus bind the sulfinamide to the active site. Molecular modeling further suggests that enantioselectivity stems from a favorable hydrophobic interaction between the aryl group of the fast-reacting (R)-arylsulfinamide and the S-1' leaving group pocket in subtilisin E.
Chiral <i>N</i>-Acyl-<i>tert</i>-butanesulfinamides: The “Safety-Catch” Principle Applied to Diastereoselective Enolate Alkylations
作者:Bradley J. Backes、Dean R. Dragoli、Jonathan A. Ellman
DOI:10.1021/jo990271w
日期:1999.7.1
Diastereoselective enolate alkylation reactions of N-acylsulfinamides and conversion of the alkylation products to a variety of enantiopure products are reported. Several sulfinamides were prepared in solution followed by acylation to provide N-acylsulfinamides. The N-acylsulfinamides were then evaluated in diastereoselective enolate alkylation reactions. Of the sulfinamides evaluated, tert-butanesulfinamide