The Asymmetric Syntheses of Methyl <small>D</small>-Digitoxoside, <small>L</small>-Oleandrose and <small>L</small>-Cymarose from Methyl Sorbate, an Achiral Precursor
addition product (+)-(3S,4S,5R)-9 possessing a 3,4-cis-dihydroxy-δ-lactone in 78% overall yield from (4S,5R)-4. The obtained (+)-(3S,4S,5R)-9 was subsequently converted to methyl D-digitoxoside (pyranoside) (12) in 13% overall yield and methyl D-digitoxoside (furanoside) (12) in 20% overall yield. The reaction of benzyl-osmundalactone (4R,5S)-3 and MeOH in the presence of Amberlyst A-26 as a basic catalyst
VERWENDUNG VON CYCLISCHEN ACETALEN/KETALEN ZUR VERBESSERTER PENETRATION VON WIRKSTOFFEN IN ZELLEN UND ORGANEN
申请人:Bayer HealthCare AG
公开号:EP1613354B1
公开(公告)日:2008-08-20
Alkoxyallene-Based De Novo Synthesis of Rare Deoxy Sugars: New Routes to L-Cymarose, L-Sarmentose, L-Diginose and L-Oleandrose
作者:Malte Brasholz、Hans-Ulrich Reißig
DOI:10.1002/ejoc.200900450
日期:2009.7
Starting from lithiated methoxyallene and lactaldehyde derivatives, the four rare 2,6-dideoxy-hexoses L-cymarose, L-sarmentose, L-diginose and L-oleandrose were synthesized in a stereodivergent fashion. Key steps towards these four target monosaccharides were the oxidative ring openings of allene-derived 2,5-dihydrofurans, diastereoselective carbonyl reductions as well as face-selective hydrogenation