Enantioselctive syntheses of sulfur analogues of flavan-3-Ols.
The first enantioselective syntheses of sulfur flavan-3-ol analogues 1-8 have been accomplished, whereby the oxygen atom of the pyran ring has been replaced by a sulfur atom. The key steps were: (a) Pd(0) catalyzed introduction of -S t-butyl group, (b) Sharpless enantioselective dihydroxylation of the alkene, (c) acid catalyzed ring closure to produce the thiopyran ring, and (d) removal of benzyl groups using N,N-dimethylaniline and AlCl(3). The compounds were isolated in high chemical and optical purity.
Sharma
Pradeep K
PK
Chemical Process Research & Development and Analytical Development, Johnson Matthey Pharmaceutical Materials Inc., Devens, MA 01434, USA. sharmap76@yahoo.com
He
Min
M
Jurayj
Jurjus
J
Gou
Da-Ming
DM
Lombardy
Richard
R
Romanczyk
Leo J
LJ
Schroeter
Hagen
H
D003500:Cyclization; D005419:Flavonoids / Q000138:chemical synthesis* / Q000737:chemistry*; D012399:Rotation; D013237:Stereoisomerism; D013457:Sulfur Compounds / Q000138:chemical synthesis* / Q000737:chemistry*
D005419:Flavonoids; D013457:Sulfur Compounds; C404987:flavan-3-ol