10.1021/jo7018812
The research focuses on the total synthesis of OSW-1, a natural saponin with significant antitumor activities, which was synthesized from (+)-dehydroisoandrosterone, L-arabinose, and D-xylose on a gram scale. The study aimed to develop a new, efficient, and practical method for synthesizing OSW-1, a promising lead compound for the development of novel antitumor drugs, due to its potent cytotoxicity against various malignant tumor cells. The synthesis was achieved in 10 linear steps with an overall yield of 6.4%, starting from (+)-dehydroisoandrosterone. The research concluded that the developed synthetic strategy was reliable, with simple workup procedures, enabling large-scale synthesis and providing a foundation for the preparation of various OSW-1 derivatives for further studies on structure-activity relationships and potential anticancer therapeutics. Key chemicals used in the process included propanenitrile, 3-methylbutylmagnesium bromide, NaOH, TBS chloride, ethylene glycol, and a variety of other reagents and solvents employed in the multi-step synthesis procedure.
10.1021/ol0483495
The study investigates the synthesis of seven-membered ring glycals through endo-selective alkynol cycloisomerization catalyzed by tungsten carbonyl. The researchers used alkynyldiols as substrates, which undergo cycloisomerization to form the corresponding seven-membered cyclic enol ethers with good yields and virtually complete regioselectivity favoring endo-mode cyclization. The study began with the conversion of D-ribose into alkynyl alcohol precursors, which were then used to produce alkynyldiols. The unexpected regioselectivity for seven-membered ring formation is likely due to the presence of the dioxolane structure tethering the terminal alkyne and diol functional groups. The study demonstrated that this transformation is general for various diastereomers of acetonide-protected alkynyldiols derived from different sugars, including D-lyxose, D-xylose, and L-arabinose. The availability of these septanose glycals could significantly advance the synthesis of structurally unusual hexoseptanose glycosides.
