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Stereoselective Synthesis of Boc-Protected cis and trans -4-Trifluoromethylprolines by Asymmetric Hydrogenation Reactions

2002; Wiley; Volume: 41; Issue: 9 Linguagem: Inglês

10.1002/1521-3773(20020503)41

1521-3773

Juan R. Del Valle, Murray Goodman,

Asymmetric Hydrogenation and Catalysis

Stereocontrolled synthesis of cis and trans-substituted prolines by a divergent approach, leads to the preparation of cis-(4S)- and trans-(4R)-trifluoromethyl-L-proline from hydroxyproline. The key pyrroline intermediates were subjected to hydrogenation (see scheme; A=sterically directed hydrogenation, B=hydroxy-directed hydrogenation; Boc=tert-butoxycarbonyl, TBS=tert-butyldimethylsilyl), to afford products in high diastereomeric excess.