摘要：

Macrosphelides A-L are a family of 16-membered macrolides whose characteristic structure and potent cell-cell adhesion inhibitory activity have attracted a number of chemists and biologists. These natural products were isolated from Macrosphaeropsis sp. FO-5050 and Periconia byssoides, and reported to inhibit adhesion of human leukemia HL-60 cells to human-umbilical-vein endothelial cells with a high selectivity. As part of our ongoing study on the structure-activity relationships of macrosphelides, we planned to develop novel strategies for the synthesis of the macrosphelide family and its analogues, which include various oxidative derivatization of Macrosphelide Core (1) and a new synthetic route for macrosphelides A and B based on ring-closing metathesis. The synthesis of our initial target compound, Macrosphelide Core (1), was accomplished starting from methyl (S)-3-hydroxybutyrate (2) in 11 steps with a 37.2% overall yield (Scheme 2). This core compound could be converted into functionalized macrosphelides, including macrosphelide A, C, and several epoxy derivatives, as shown in Scheme 3. In addition, to achieve effective synthesis of macrosphelides A and B via a common synthetic process, we selected the macrocycle 35 as their precursor, which contains distinguishable protecting groups. For the construction of the macrocyclic system, ring-closing metathesis of 34 was our choice. On the basis of this strategy, we established the total synthesis of macrosphelides A and B from two commercially available chiral materials, methyl (S)-(+)-3-hydroxybutyrate (2) and methyl (S)-(-)-lactate (19) with high efficiency. In this meeting, details of these results will be discussed.

展开