NEW METHODS FOR STEREOSELECTIVE ADDITIONS TO CARBONYLS

描述：首席调查员注意到他正在从事一项 研究计划，其目的是发现新的立体选择性 以及有机合成中的化学选择性反应和试剂。他 声称他使用机械论有机化学的工具来揭示 高强度反应中不对称诱导的起源 选择性级别，然后使用这些结果作为 对表现出类似水平的新反应的调查 立体选择性。首席调查员表示，他是 刘易斯酸介导的亲核机理继续研究 他已经开发出一种方法，可以让他 为了确定这些反应中的立体特异性水平，以及 从而区分SN1和SN2机制。值得注意的是 在本提案中，描述了一种相关的方法，该方法 用于手性无环缩醛。据说这些底物具有 之所以被选中是因为它们表现出一种不同寻常的立体化学依赖 缩醛的烷基性质。这些机械论研究 以带领首席研究员探索新方法而著称 通过在Diels-Alder反应中实现远程不对称诱导 手性乙烯基氧卡宾离子。他表示，他将延长这一期限 分子内Diels-Alder反应，这种方法也是 应用于HMG-CoA还原酶抑制剂的合成 二氢压实。

DESCRIPTION: The principal investigator notes that he is engaged in a research program, the aims of which are to discover new stereoselective and chemoselective reactions and reagents in organic synthesis. He states that he uses the tools of mechanistic organic chemistry to uncover the origin of asymmetric induction in reactions that proceed with high levels of selectivity, then uses these results as a guide in the investigation of new reactions that exhibit similar levels of stereoselectivity. The principal investigator indicates that he is continuing to study the mechanism of Lewis acid mediated nucleophilic additions to acetals and that he has developed a method which allows him to determine the level of stereospecificity in these reactions and thereby distinguish between an SN1 and an SN2 mechanism. It is noted that in this proposal, a related method is described that is being applied to chiral acyclic acetals. These substrates were said to have been chosen because they display an unusual stereochemical dependence on the nature of the alkyl group of the acetal. These mechanistic studies are noted to have led the principal investigator to explore new methods for achieving remote asymmetric induction in the Diels-Alder reaction via chiral vinyl oxocarbenium ions. He indicates that he is extending this to intramolecular Diels-Alder reactions and that this method is also being applied to the synthesis of the HMG-CoA reductase inhibitor dihydrocompactin.