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3,6‐Thioanhydro sugar derivatives. An enantiospecific synthesis of (2 R ,3 R ,4 S )‐3‐benzyloxy‐4‐hydroxy‐2‐[( R )‐1‐benzyloxy‐4‐hydroxybutyl]thiolane as the key intermediate for thioswainsonine
Author(s) -
Izquierdo Isidoro,
Plaza Maria T.,
RamYírez Antonio,
Aragón Fida
Publication year - 1996
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570330440
Subject(s) - chemistry , aluminum hydride , hydrolysis , lithium (medication) , derivative (finance) , hydride , acid hydrolysis , catalytic hydrogenation , stereochemistry , catalysis , medicinal chemistry , organic chemistry , metal , medicine , methoxide , financial economics , economics , endocrinology
Abstract Methyl 2‐ O ‐benzyl‐3,6‐thioanhydro‐α‐D‐mannopyranoside ( 9 ) was obtained in eight steps from the commercially available methyl α‐D‐glucopyranoside. Compound 9 was transformed into (2 R ,3 R ,4 S )‐3‐benzyloxy‐4‐hydroxy‐2‐[( R )‐1‐benzyloxy‐4‐hydroxybutyl]thiolane ( 14 ) by acid hydrolysis of its 2,4‐di‐ O ‐benzyl derivative 10 followed by reaction of the not isolated 2,4‐di‐ O ‐benzyl‐3,6‐thioanhydro‐D‐mannose ( 11 ) with ethoxycarbonylmethylenetriphenylphosphorane to give an = 1:1 E/Z mixture of the corresponding α,β‐unsaturated ester ( 12 ). Finally, catalytic hydrogenation of 12 to ethyl ( R )‐4‐benzyloxy‐4‐[(2′ R )3′ R ,4′ S )‐3′‐benzyloxy‐4′‐hydroxythiolan‐2′‐yl]butanoate ( 13 ) and subsequent reduction with lithium aluminum hydride gave the title compound 14 .