To B-E or not to B-E? Developing New Boranes and Boration Reactions

生存还是毁灭？

• 批准号: RGPIN-2016-04302
• 负责人: Westcott, Stephen
• 金额: $ 4.44万
• 依托单位: Mount Allison University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=614973
• 关键词: Developing; New; Boranes; Boration; Reactions

The addition of boron-element (B-E, where E = H, B, Si, etc) bonds to unsaturated compounds constitutes a family of remarkably important reactions in organic synthesis for the production of new compounds for the pharmaceutical and agricultural industries. Reactions of B-E where E is a heavier main group elements (E = silicon, germanium, etc) usually result in organodimetalloid compounds which are highly versatile building blocks that are otherwise difficult to synthesize. Given the intensity of interest in this area it is somewhat surprising that relatively little is known about the analogous addition chemistry of compounds containing single B-E bonds where E is either sulfur (S), selenium (Se), or phosphorus (P). To address this limitation in boron chemistry, this proposal will focus on expanding the scope and chemistry of relatively unknown B-E (E = P, S, Se) compounds. For instance, we have recently reported a new phosphinoboronate ester (Ph2PBpin, pin = pinacolato) that can be used as a platform for the synthesis of a wide range of new compounds. Likewise, we have prepared new starting materials containing discrete B-S and B-Se bonds and propose to further investigate their addition chemistry. The first project in this study will be to generate additional B-E (E = P, S, Se) compounds, where we can electronically and sterically vary the groups on the boron atom and/or the main group element. A variety of substrates will be examined in addition reactions to assess the efficacy of these simple new boron-main group compounds. New reagents will also be investigated for their ability to react with aldehydes (and ketones) already containing a phosphide (PR2) or sulfide group (SR). The resulting products will be examined for their potential to add to metals that can be used as catalysts. We have also found that Ph2PBpin adds to phenylacetylene (PhCCH) in the presence of a metal catalyst to give an unusual 1,1-addition product. We will expand the scope of this reaction by varying the alkynes and the catalysts to see if we can generate different products. The 1,1-addition products in these reactions will subsequently be investigated as ambiphilic (containing a donor and acceptor group) ligands for transition metals. Finally, while significant advances have been made in catalytic boration chemistry, the full potential of these reagents in organic synthesis is not yet close to being realized. Finally, we propose to investigate these new B-E species for their use in the borylformylation of alkynes. The related hydroformylation is one of the most important catalytic reactions in industry today. The last project may be challenging but it has the potential to generate novel chemical reactions. As always, this work will be used to attract, and train, the next generation of Wild Toad (the name of our group) researchers who will hopefully make a considerable impact in Canadian science, technology, medicine and education.

硼元素（B-E，其中E = H， B， Si等）键加到不饱和化合物上构成了有机合成中一系列非常重要的反应，用于制药和农业工业的新化合物的生产。当E是较重的主族元素（E =硅，锗等）时，B-E的反应通常会产生有机双金属化合物，这些化合物是高度通用的构建块，否则很难合成。考虑到人们对这一领域的强烈兴趣，人们对含有单B-E键的化合物的类似加成化学反应知之甚少，其中E是硫(S)、硒（Se）或磷(P)，这多少有些令人惊讶。为了解决硼化学中的这一限制，本提案将重点扩展相对未知的B-E （E = P， S, Se）化合物的范围和化学性质。例如，我们最近报道了一种新的膦硼酸酯（Ph2PBpin, pin = pinacolato），它可以用作合成各种新化合物的平台。同样，我们也制备了含有离散B-S和B-Se键的新起始材料，并建议进一步研究它们的加成化学。本研究的第一个项目将是生成额外的B-E （E = P， S, Se）化合物，我们可以在电子和空间上改变硼原子和/或主族元素上的基团。多种底物将在加成反应中进行检测，以评估这些简单的新型硼主基团化合物的功效。新试剂还将研究它们与已经含有磷化物（PR2）或硫化物基团（SR）的醛（和酮）反应的能力。由此产生的产品将被检查是否有可能添加到可以用作催化剂的金属中。我们还发现Ph2PBpin在金属催化剂的存在下加入到苯乙炔（PhCCH）中，得到不寻常的1,1加成产物。我们将通过改变炔烃和催化剂来扩大这个反应的范围，看看是否能生成不同的产物。这些反应中的1,1加成产物随后将被研究为过渡金属的两亲性配体（包含供体和受体基团）。最后，虽然在催化硼化化学方面取得了重大进展，但这些试剂在有机合成中的全部潜力尚未接近实现。最后，我们建议研究这些新的B-E物种在炔的硼酰基甲酰化中的应用。相关的氢甲酰化反应是当今工业上最重要的催化反应之一。最后一个项目可能具有挑战性，但它有可能产生新的化学反应。一如既往，这项工作将用于吸引和培养下一代的“野蟾蜍”（我们小组的名称）研究人员，他们有望在加拿大的科学、技术、医学和教育领域产生相当大的影响。