Ivasyshyn Viktor, Smit Hans, Chiechi Ryan C
Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
ACS Omega. 2019 Aug 19;4(9):14140-14150. doi: 10.1021/acsomega.9b02131. eCollection 2019 Aug 27.
This paper describes the synthesis of a discrete unit of hominal bis(-CF). The controlled introduction of fluorine atoms is a powerful synthetic tool to introduce dipole moments with minimal impact to sterics. Poly(vinylidene difluoride) is a striking example of the influence of fluorine atoms, which impart ferroelectric behavior from the alignment of the dipole moments of CF units; however, it is prepared via direct polymerization of vinylidene difluoride. Thus, a different synthetic pathway is required to produce synthons containing discrete numbers of CF groups in a hominal relation to each other. We found out that, in the case of short chains, the consecutive deoxofluorination of sequentially introduced keto groups is inefficient, as it requires harsh conditions and decreasing yields at each step. To solve this problem, we combined the selective desulfurative fluorination of dithiolanes with pyridinium fluoride and the deoxofluorination of keto groups with morpholinosulfur trifluoride. This strategy is highly reproducible and scalable, allowing the synthesis of the hominal bis(-CF) fragment as a shelf-stable tosylate, which can be used to install discrete chains of hominal bis(-CF) on a variety of synthons and monomers.
本文描述了一种人源双（-CF）离散单元的合成。氟原子的可控引入是一种强大的合成工具，可在对空间位阻影响最小的情况下引入偶极矩。聚偏二氟乙烯就是氟原子影响的一个显著例子，CF单元的偶极矩排列赋予了它铁电行为；然而，它是通过偏二氟乙烯的直接聚合制备的。因此，需要一条不同的合成途径来制备彼此呈人源关系且含有离散数量CF基团的合成子。我们发现，对于短链而言，依次引入的酮基的连续脱氧氟化效率低下，因为这需要苛刻的条件且每一步产率都会降低。为了解决这个问题，我们将二硫杂环戊烷与氟化吡啶的选择性脱硫氟化反应和酮基与吗啉三氟硫化物的脱氧氟化反应结合起来。该策略具有高度的可重复性和可扩展性，能够合成作为货架稳定甲苯磺酸盐的人源双（-CF）片段，可用于在各种合成子和单体上安装人源双（-CF）的离散链。
