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A Novel Route for the Synthesis of Deoxy Fluoro Sugars and Nucleosides
Author(s) -
Mikhailopulo Igor A.,
Sivets Grigorii G.
Publication year - 1999
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/(sici)1522-2675(19991110)82:11<2052::aid-hlca2052>3.0.co;2-7
Subject(s) - chemistry , yield (engineering) , riboside , epoxide , derivative (finance) , anomer , pyrimidine , medicinal chemistry , stereochemistry , organic chemistry , catalysis , biochemistry , materials science , economics , financial economics , metallurgy
The reaction of (diethylamino)sulfur trifluoride (DAST) with methyl 5‐ O ‐benzoyl‐ β ‐ D ‐xylofuranoside ( 1 ) followed by column chromatography afforded the riboside 2 (62%) and the ribo ‐epoxide 3 (18%) ( Scheme 1 ). Under similar reaction conditions, the α ‐ D ‐anomer 4 gave the riboside 5 and the difluoride 6 in 60 and 9% yield, respectively. Treatment of the β ‐ D ‐xyloside 10 with DAST gave, after chromatographic purification, the riboside 11 as the principal product (48%; Scheme 2 ). These results suggest that the C(3)−O−SF 2 NEt 2 derivatives were initially formed in the case of the xylosides studied. The distinctive feature of the reaction of DAST with the β ‐ D ‐arabinoside 12 consists in the formation of a 3‐ or 5‐benzylideneoxoniumyl‐substituted intermediate on one of the consecutive transformations, which finally give rise to the inversion of the configuration at C(3) affording the xylosides 17 (18%) and 18 (55%); the lyxoside 14 was also isolated from the reaction mixture in a yield of 25% ( Scheme 3 ). In the presence of the non‐participating 5‐ O ‐trityl group, i.e. , from the reaction products of 21 with DAST, the compounds 23 and 24 were isolated in 16 and 52% yield, respectively ( Scheme 4 ). It may be thus reasonable to conclude that, in the case of the β ‐ D ‐arabinosides 12 and 21 , the principal route of the reaction is the formation of the intermediate C(2)−O−SF 2 NEt 2 derivative. Unlike 21 , the α ‐ D ‐arabinoside 26 was converted to the lyxo ‐epoxide 25 (53%) and the lyxoside 27 (14%), which implies the intermediate formation of the C(3)−O−SF 2 NEt 2 derivative ( Scheme 5 ).