Fg. Calvoflores et al., APPLICATIONS OF CYCLIC SULFATES OF VIC-DIOLS - SYNTHESIS OF EPISULFIDES, OLEFINS, AND THIO SUGARS, Journal of organic chemistry, 62(12), 1997, pp. 3944-3961
A new efficient and expeditious one-pot synthesis of thiiranes and ole
fins from cyclic sulfates of vic-diols is described. Opening of cyclic
sulfates with potassium thioacetate or potassium thiocyanate followed
by treatment with sodium methoxide led to episulfides. Olefins were o
btained when potassium selenocyanate was used as nucleophile, and the
obtained monoesters were treated with sodium borohydride. This method
was applied to acyclic polyols derived from chiral glycerine, 1,2-isop
ropylidenehexofuranoses with different subtituents at C-3, and dimethy
l acetals derived from pentoses and hexoses. The methodology is highly
versatile, and its applicability has been demonstrated by the synthes
is of different 4- and 5-thiosugars by opening of the thiirane ring wi
th sodium acetate or lithium aluminum hydride. Reduction with lithium
aluminum hydride of the thiocyanate sulfate potassium salt obtained by
the opening of cyclic sulfate with KSCN allowed the direct synthesis
of 5-deoxy-4-thio- and 6-deoxy-5-thiosugars. Cyclic thiosugars with th
e sulfur atom in the ring are obtained by acidic hydrolysis of the 5-t
hiol derivatives of 1,2-O-isopropylidenehexofuranoses and 4-thiopentos
e dimethyl acetals. Using this method, an efficient synthesis of 5-thi
o-L-fucose as well as the synthesis of 2,5-dideoxy-4-thiofuranose is d
escribed.