手性分子在医药、材料、化学、生物等领域具有重要的作用,所以它们的快速获取一直是众多科研工作者研究的兴趣所在。手性分子通常有三种获取方法,分别是天然存在的手性分子进一步转化、不对称催化、动力学拆分。不对称催化和动力学拆分在过去几十年内得到了快速发展,随之而来的问题也凸显出来:比如很多反应在得到高对映选择性后的继续发展缺少了动力,逐渐远离了研究的热点;比如动力学拆分的底物类型依然显得局限性较大,能发生动力学拆分的反应的发现缺少指导性策略。为解决这些问题,我们提出了非手性底物取代基添加(Substituent Addition to Achiral Substrate,SAAS)的方法,可以为上述的多个难点和挑战提供一定的解决方案。如图1a所示,Enders,Suzuki于2006年在不对称分子内benzoin反应的研究中取得了突破[1,2];随后游书力课题组也做出了突出的工作[3,4]。遗憾的是,此反应的进一步研究未能取得突破。我们将取代基添加的方法引入这一人名反应,发展出了一系列导向多立体中心手性分子生成的分子内benzoin反应[5,6,7]。更重要的是,取代基添加法将此反应的潜力和活力重新激发出来,并揭示了分子内benzoin反应的多个新反应模式,开发出了它的更多新应用,在机理方面也取得了突破,发现了多个有别于传统认识的新观点。另一方面,也为能参与动力学拆分的反应的发现提供了新的指导方法。进一步研究标明,这一方法不仅可以应用于分子内benzoin反应,还可以应用于不对称催化领域的其他反应,所以是一个具有普遍适用性的策略。
The solvation of carbon dioxide in sea water plays an important role in the carbon circle and the world climate. The salting-out/salting-in mechanism of CO2 in electrolyte solutions still remains elusive at molecule l...
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The solvation of carbon dioxide in sea water plays an important role in the carbon circle and the world climate. The salting-out/salting-in mechanism of CO2 in electrolyte solutions still remains elusive at molecule level. The ability of ion salting-out/salting-in CO2 in electrolyte solution follows Hofmeister Series and the change of water mobility induced by salts can be predicted by the viscosity B-coefficients. In this work, the chemical potential of carbon dioxide and the dynamic properties of water in aqueous NaCl, KF and NaClO4 solutions are calculated and analyzed. According to the viscosity B-coefficients, NaClO4 （0.012） should salt out the carbon dioxide relative to in pure water, but the opposite effect is observed for it. Our simulation results suggest that the salting-in effect of NaClO4 is due to the strongly direct anion-CO2 interaction. The inconsistency between＂ Hofmeister Series and the viscosity B-coefficient suggests that it is not always right to indicate whether a salt belongs to salting-in or salting-out just from these properties of the salt solution in the absence of solute.
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