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

硼元素(B-E，式中E=H、B、Si等)与不饱和化合物的加成反应是有机合成中一类非常重要的反应，用于生产制药和农业用的新化合物。B-E的反应，其中E是较重的主族元素(E=硅、锗等)，通常会产生有机双金属化合物，这些化合物是用途非常广泛的构建块，否则很难合成。考虑到人们对这一领域的浓厚兴趣，有些令人惊讶的是，人们对含有单一B-E键的化合物的类似加成化学知之甚少，其中E是硫(S)、硒(Se)或磷(P)。为了解决硼化学中的这一限制，本建议将重点扩大相对未知的B-E(E=P，S，Se)化合物的范围和化学。例如，我们最近报道了一种新的膦硼酸酯(Ph2PBpin，pin=pinacolato)，它可以用作合成一系列新化合物的平台。同样，我们制备了含有离散的B-S键和B-Se键的新的起始材料，并建议进一步研究它们的加成化学。这项研究的第一个项目将是产生额外的B-E(E=P，S，Se)化合物，其中我们可以电子和空间地改变硼原子和/或主族元素上的基团。除了反应外，还将检查各种底物，以评估这些简单的新的硼主族化合物的有效性。还将研究新试剂与已含有磷化物(PR2)或硫化物(SR)的醛(和酮)反应的能力。所得产品将被检查它们是否有可能添加到可用作催化剂的金属中。我们还发现，在金属催化剂的存在下，Ph2PBpin与苯乙炔(PhCCH)发生加成反应，生成不寻常的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，看看我们是否可以产生不同的产物。这些反应中的1，1-加成产物随后将作为过渡金属的双亲(包含给体和受体基团)配体进行研究。最后，虽然在催化硼化化学方面已经取得了重大进展，但这些试剂在有机合成中的全部潜力还没有接近实现。最后，我们建议研究这些新的B-E物种在炔烃的硼甲酰化反应中的应用。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，这项工作将被用来吸引和培训下一代野生蟾蜍(我们团队的名字)研究人员，他们有望对加拿大的科学、技术、医学和教育产生相当大的影响。**

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. **