DEVELOPMENT OF USEFUL REACTIONS USING THE NOVEL LEAVING GROUP, MONOCHLATE

点击翻译按钮获取中文摘要

One of the important and most widely studied organic reactions is nucleophilic substitution at a saturated carbon. Although sulfonates are the most common leaving groups, we sometimes encounter problems such as low reactivity of the methanesulfonates (mesylates; Ms=CHィイD23ィエD2SOィイD22ィエD2-) and instability of the trifluoromethanesulfonates (triflates; Tf=CFィイD23ィエD2SOィイD22ィエD2-). We have found that chloromethanesulfonates (monochlate; Mc=C1CHィイD22ィエD2SOィイD22ィエD2-) served as an extremely efficient leaving group, which exceeds the corresponding mesylates and triflates. Inversion of a wide range of secondary alcohols using the monochlates with cesium acetate in the presence of 18-crown-6 in benzene under reflux has been performed to give the acetates with complete inversion of the configuration in high yields. We have examined further studies on the monochlate as the new and efficient leaving group and found several efficient reactions using monochlates; i.e., (1) rearrangement of the carbon-carbon bond, (2) conversion of secondary alcohols into azides with inversion of the configuration, and (3) conversion of a β-alkoxy primary alcohol into a nitrile.