Absolute stereostructures of cell-adhesion inhibitors, macrosphelides C, E–G and I, produced by a Periconia species separated from an Aplysia sea hare
Macrosphelides EâI have been isolated, along with known macrosphelides A and C, from a strain of Periconia byssoides originally separated from the sea hare Aplysia kurodai, and the absolute stereostructures of macrosphelides EâG and I have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques and some chemical transformations. In addition, the absolute configuration of macrosphelide C, previously undetermined, has been established by X-ray analysis and application of the modified Mosher method. Macrosphelides EâH inhibited the adhesion of human-leukaemia HL-60 cells to HUVEC.
A highly enantioselective one-pot synthesis of homoallylic alcohols via tandem asymmetric allyl transfer/olefin cross metathesis
作者:Cheng-Hsia Angeline Lee、Teck-Peng Loh
DOI:10.1016/j.tetlet.2005.11.078
日期:2006.1
A highlyenantioselective one-pot synthesis of linear homoallylic alcohols with terminal ester functionality has been achieved. The reactions were controlled by ordered addition of reagents and catalysts, ensuring complete consumption of aldehyde. The synthetic utility of this strategy has been demonstrated in a short synthesis of a low boiling point intermediate for grahamimycin A.