利用Pd(0)催化的Stille偶联反应分别从甲基α,d-吡喃葡萄糖苷和甲基α,d-甘露吡喃糖苷分别合成了(+)-4- Epi -Gabosine A 1和(-)-Gabosine A 2关键步骤。另一方面,已经由甲基α,d-吡喃葡萄糖苷和甲基α,d合成了(+)-4-表-葡萄糖苷E 3和(-)-葡萄糖苷E 4。-甘露吡喃糖苷分别通过利用DMAP催化的Morita-Baylis-Hillman反应作为关键步骤。糖衍生的环状烯酮的C-6位上存在乙酰基可防止MBH加合物的芳构化。还描述了一种合理的机制。
An iodocyclization approach toward diastereoselective synthesis of highly functionalized tetrasubstituted tetrahydrofurans with 2,5-trans and 2,5-cis relationships from pyranoside derived acyclic oximes
摘要:
An efficient method to obtain novel tetrasubstituted tetrahydrofurans with C2 and C5 substitution in trans- and cis-relative configurations has been reported. (C) 2007 Elsevier Ltd. All rights reserved.
A highly stereoselective totalsynthesis of (+)-varitriol, an antitumor natural product, has been achieved for the first time from commercially available methyl alpha,D-mannopyranoside and 2,6-dihydroxybenzoic acid.