Control of Conformation and Reactivity in Pentafluorosulfanyl and Tetrafluorosulfanyl Substituted Aliphatic Compounds

在这个由化学系化学合成计划资助的项目中，奥尔巴尼大学的约翰·韦尔奇教授正在开发新的含氟官能团。 含氟化合物广泛应用于生命科学和材料研究。 近20%的药物和40%的农用化学品含有氟。75年来，氟化和氟化官能团为材料增加了价值和实用性，但越来越明显的是，这些有用的取代基可能伴随着不期望的环境影响。 韦尔奇教授正在培训研究生处理反应性极强的试剂，以制备新型氟化反应物。Welch教授经营并向科学界提供了一个专用实验室，该实验室配备了必要的基础设施，用于制备，纯化和表征液体和气体反应性氟化中间体和半导体。 研究了脂肪族含氟高价硫化合物的结构与反应活性之间的关系。 虽然五氟硫烷基的化学性质还处于起步阶段，但韦尔奇小组正在探索使用对环境更友好的高价氟化硫化合物来提供所需的脱硫效果，同时减轻不希望的方面，例如，通过对环境无害的方式分解。 正在探索空间需求、电负性和偶极矩对含氟化高价硫的β-内酰胺、氨基酸和肽的物理性质、构象和选择性的影响。三氟甲基取代在SF 5-基团（即新的SF 4（CF 3）基团）中的作用正在研究中。在比较SF 5和SF 4（CF 3）取代基时，将检查选择性和反应性的差异。将作出努力，以确定是否与这两个新的，重氟化取代基的偶极矩或吸电子能力的趋势，这种差异。

In this project funded by the Chemical Synthesis program of the Chemistry Division, Professor John Welch of the University at Albany is developing new fluorine containing functional groups. Fluorinated compounds are widely employed in life sciences and materials research. Nearly 20% of all pharmaceuticals and 40% of all agrochemicals contain fluorine. Fluorination and fluorinated functional groups have added value and utility to materials for 75 years yet it has been increasingly apparent that these useful substituents can be accompanied by undesirable environmental effects. Prof. Welch is training graduate students to handle extraordinarily reactive reagents to prepare novel fluorinated reactants. Prof. Welch operates and makes available to the scientific community a dedicated laboratory equipped with the necessary infrastructure for the preparation, purification and characterization of both liquid and gaseous reactive fluorinated intermediates and synthons. The relationship between structure and reactivity of aliphatic fluorinated hypervalent sulfur compounds is under investigation. Although the chemistry of the pentafluorosulfanyl group is very much in its infancy, the Welch group is exploring the use of environmentally more benign hypervalent fluorinated sulfur compounds to deliver the desired effects of fluorination while mitigating the undesirable aspects, e.g., by decomposing in an environmentally benign manner. The influence of steric demand, electronegativity and dipole moment on the physical properties, conformation, and selectivity of beta-lactams, amino acids and peptides containing fluorinated hypervalent sulfur is being explored. The role of trifluoromethyl substitution in the SF5-group (i.e. the new SF4(CF3) group) is under investigation. In comparing the SF5 and SF4(CF3) substituents, differences in selectivity and reactivity will be examined. An effort will be made to establish whether such differences correlate with trends in dipole moment or electron-withdrawing ability of these two new, heavily fluorinated substituents.