New Synthetic Methods Based on Titanacyclopropanes

韦恩州立大学化学系的Jin K. Cha教授将在化学合成项目中探索低价钛介导的酯类环丙化和相关交叉偶联反应的合成应用。在Kulinkovich最初发现的基础上，Cha教授的小组开发了烯烃交换介导的变体，扩大了Kulinkovich环丙烷化的范围，并为机械相关的交叉偶联反应铺平了道路。具体目标包括关键环丙烷化反应的机理研究；低价钛介导的烯丙醇和均烯丙醇烷基化和交叉偶联反应以及环丙醇与一系列亲电试剂在C-C成键反应中的开环作用。包括过渡金属催化的开环反应。这些反应代表了库林科维奇试剂的新用途，具有广泛的范围和明确的立体化学结果。特别强调将放在高效率和收敛，这是可能的片段耦合。查教授的方法有利于环境友好的合成，为制药、化学、农业和材料科学提供了有利的技术。此外，该项目将为同事提供培训，从本科生研究参与者到博士后，包括那些历史上在物理科学领域代表性不足的群体。

In this project funded by the Chemical Synthesis Program of the Chemistry Division, Professor Jin K. Cha of the Department of Chemistry at Wayne State University will explore synthetic applications of the low valent titanium-mediated cyclopropanation of esters and related cross-coupling reactions. By building on the original discovery by Kulinkovich, Professor Cha's group developed the olefin exchange-mediated variant to broaden the scope of the Kulinkovich cyclopropanation and pave the way for mechanistically related cross-coupling reactions. The specific goals include mechanistic studies of the key cyclopropananation reaction; low-valent titanium-mediated alkylation and cross-coupling reactions of allylic and homoallylic alcohols; and ring opening of cyclopropanols with a range of electrophiles in C-C bond forming reactions. Included are transition metal-catalyzed ring opening reactions. These reactions represent new uses of the Kulinkovich reagent with a broad scope and the well-defined stereochemical outcome. Particular emphasis will be placed at high efficiency and convergence, which is made possible by segment coupling.Professor Cha's approach lends itself to environmentally benign syntheses, which offer enabling technology to the pharmaceutical, chemical, agricultural industry, and materials science. Additionally, this project will provide training of coworkers, from undergraduate research participants to post-doctoral, including those from groups historically underrepresented in the physical sciences.