Versatile Synthesis of Chlorophylls and Bacteriochlorophylls for Fundamental Studies in Photosynthesis

在化学系化学合成项目的支持下，北卡罗来纳州立大学的乔纳森·s·林赛教授将研究如何合成进行光合作用的主要色素。这些色素是众所周知的叶绿素，它赋予植物特有的绿色，以及较少为人所知的细菌叶绿素。这些研究将开发出创造用于光合作用的自然分子的方法。开展这项工作的原因是，创造这些分子及其变体的能力，将允许研究有关其基本化学的深层次问题，并探索光能转化为化学能的各个方面。拟议活动的更广泛影响将包括高中科学教师的专业发展，以改善学校光合作用的教学（通过基于叶绿素的实验），并激励高中生学习STEM，以及将先前开发的叶绿素实验扩展到中学。制备（细菌）叶绿素和类似物的合成方法的缺乏构成了光合作用科学的智力和技术缺陷。林赛实验室的目标是通过开发合成这种有价值的大环的可靠方法来填补这一空白。一个漫不经心的观察者可能会认为叶绿素的合成是一个完整的故事——这是大错特错的。事实上，还没有任何一种小分子合成起始材料通过化学合成转化成叶绿素，也没有任何试图合成细菌叶绿素的报道。拟议的工作将建立在光合作用四吡咯全合成的第一个例子的基础上，其中必要的立体化学特征通过既定的不对称方法与简单的早期前体一起安装。要达到的目标是进一步简化最近发展的合成路线；探索一种逐步脱氢的方法，提供从细菌氯到氯和卟啉的途径；检查后期衍生化方法，以安装关键的外围功能群；通过这样做，我们可以接触到一些具有代表性的光合作用四吡咯。将与美国、德国和日本的实验室进行6项使用合成（细菌）叶绿素的合作。将尽一切努力使用广泛可得的实际方法。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Synthesis program in the Division of Chemistry, Professor Jonathan S. Lindsey of North Carolina State University will study how to synthesize the chief pigments that carry out photosynthesis. Those pigments are the well-known chlorophylls that give plants their characteristic green color, and the lesser-known bacteriochlorophylls of selected bacteria. The studies will develop methods for creating Nature’s molecules for photosynthesis. The reason for carrying out this work is that the ability to create these molecules, and variants thereof, will allow examination of deep questions concerning their basic chemistry and to probe aspects of the conversion of light into chemical energy. The broader impacts of the proposed activity will include the professional development of high school science teachers to improve teaching of photosynthesis (via a chlorophyll-based experiment) in schools and to inspire high school students to STEM, and the expanded deployment to middle schools of a previously developed chlorophyll experiment.The lack of synthetic methods for preparing (bacterio)chlorophylls and analogues constitutes an intellectual and technical deficit in the photosynthetic sciences. The Lindsey lab aims to fill this gap by developing robust methods for synthesis of such valuable macrocycles. A casual observer may consider the synthesis of chlorophyll to be a finished story – and this couldn't be more wrong. In fact, no small-molecule synthetic starting material has ever been converted to a chlorophyll by chemical synthesis, and there are no reports of any attempts to synthesize bacteriochlorophylls. The proposed work will build on the first example of the total synthesis of a photosynthetic tetrapyrrole, wherein the requisite stereochemical features are installed with simple early precursors via established asymmetric methods. Objectives to be met are to further streamline a recently developed synthetic route; explore a step-down dehydrogenation approach that provides access from bacteriochlorins to chlorins and porphyrins; examine late-stage derivatization approaches to install critical peripheral functional groups; and in so doing demonstrate access to a handful of representative members of photosynthetic tetrapyrroles. Six collaborations using synthetic (bacterio)chlorophylls will be undertaken with labs in the US, Germany, and Japan. Every effort will be made to use practical methods that are broadly accessible.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.