New Polyhydroxylated Pyrrolidines Derived from Enantiopure 3,6-Dihydro-2H-1,2-oxazines
摘要:
[GRAPHICS]Diastereoselective hydroborations of enantiopure 3,6-dihydro-2H-1,2-oxazines led to dihydroxy-substituted 1,2-oxazines. Samarium diiodide-induced N-O bond cleavage generated 1,4-amino alcohols which were recyclized to polyhydroxylated pyrrolidines which are potential glycosidase inhibitors.
New Polyhydroxylated Pyrrolidines Derived from Enantiopure 3,6-Dihydro-2H-1,2-oxazines
摘要:
[GRAPHICS]Diastereoselective hydroborations of enantiopure 3,6-dihydro-2H-1,2-oxazines led to dihydroxy-substituted 1,2-oxazines. Samarium diiodide-induced N-O bond cleavage generated 1,4-amino alcohols which were recyclized to polyhydroxylated pyrrolidines which are potential glycosidase inhibitors.
Stereodivergent Syntheses of Highly Substituted Enantiopure 4-Alkoxy-3,6-dihydro-2H-1,2-oxazines by Addition of Lithiated Alkoxyallenes to Carbohydrate-Derived Aldonitrones
Additions of lithiated alkoxyallenes to D-glyceraldehyde-based nitrones 1 and 2 did not provide the expected hydroxylamine derivatives. Instead, a novel [3+3] cyclization process furnished 4-alkoxy-3,6-dihydro-2H-1,2-oxazines 9–14 with excellent syn selectivities and in moderate to good yields. Through precomplexation of the nitrones the corresponding anti-configured 1,2-oxazines 9, 10 and 13 could
Internally Protected Amino Sugar Equivalents from Enantiopure 1,2‐Oxazines: Synthesis of Variably Configured Carbohydrates with C‐Branched Amino Sugar Units
作者:Fabian Pfrengle、Hans‐Ulrich Reissig
DOI:10.1002/chem.201001060
日期:2010.10.18
precursors allowed the synthesis of homo‐oligomeric di‐ and trisaccharides 44, 46 and 47 or a hybrid trisaccharide 51 with natural carbohydrates. Access to a bivalent amino sugar derivative 54 was accomplished by reaction of rearrangement product 10 with 1,5‐pentanediol. Alternatively, when a protected L‐serine derivative was employed as glycosyl acceptor, the glycosylated amino acid 60 was efficiently prepared
[GRAPHICS]Diastereoselective hydroborations of enantiopure 3,6-dihydro-2H-1,2-oxazines led to dihydroxy-substituted 1,2-oxazines. Samarium diiodide-induced N-O bond cleavage generated 1,4-amino alcohols which were recyclized to polyhydroxylated pyrrolidines which are potential glycosidase inhibitors.