Iridium-catalyzed highly selective reactions

铱催化的高选择性反应

基本信息

批准号：
18550098
负责人：
TAKEUCHI Ryo
金额：
$ 2.64万
依托单位：
Aoyama Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18550098/
关键词：
iridium allylic alkylation asymmetric synthesis phosphoramidite cyclotrimerization regioselectivity

项目摘要

We have studied the following reactions.(1) Asymmetric allylic alkylation is one of the most powerful tools for constructing a new chiral center via a carbon-carbon bond-forming reaction from an achiral substrate. A challenging topic in this area is the regio- and enantioselective allylic alkylation of nonsymmetrical substrates. Chiral phosphoramidite ligands have become important in transition metal-asymmetric synthesis. Helmchen first used binaphthol-based phosphoramidites for iridium-catalyzed enantioselective allylic alkylation. We designed a novel phosphoramidite P(OR)_2(amide)ligand. The planarity of the amide group strongly contributes to a more rigid chiral space. Furthermore, such a phosphoramidite ligand is expected to act as a chiral bidentate ligand through coordination of the carbonyl oxygen and phosphorous atom to the central metal. The efficiency of the ligand was examined by the reaction of cinhamyl acetate with diethyl sodiomalonate in the presence of 2 mol% of [Ir(cod)Cl]_2 and 4 mol% of ligand. The best result was obtained with a ligand bearing an oxazolidinone moiety. The alkylated product was obtained in 94% yield with 93% ee without LiCl.(2) Polysubstituted benzenes are a common structural component of naturally occurring biologically active molecules. The regioselective cyclotrimerization of two or three different monoynes is a new and efficient route to polysubstituted benzenes. However, it can be difficult to control the regioselectivity. Methyl propiolate reacted with 2 molecules of 1-alkyne to give 3, 5-disubstituted benzoate in high yield in the presence of a catalytic amount of [Ir(cod)Cl]_2 and FDPPE. The reaction of ethynyl p-tolyl sulfone with various 1-alkynes gave the corresponding products in high yields

我们研究了以下反应。(1)不对称烯丙基烷基化是通过非手性底物的碳-碳成键反应构建新手性中心的最有力的工具之一。该领域的一个具有挑战性的主题是非对称底物的区域和对映选择性烯丙基烷基化。手性亚磷酰胺配体在过渡金属不对称合成中已变得重要。 Helmchen 首先使用联萘酚基亚磷酰胺进行铱催化的对映选择性烯丙基烷基化。我们设计了一种新型亚磷酰胺P(OR)_2(酰胺)配体。酰胺基团的平面性极大地有助于形成更刚性的手性空间。此外，这种亚磷酰胺配体有望通过羰基氧和磷原子与中心金属的配位而充当手性二齿配体。通过乙酸肉桂酯与丙二酸二乙酯在2mol％的[Ir(cod)Cl]_2和4mol％配体存在下的反应来检查配体的效率。使用带有恶唑烷酮部分的配体获得了最好的结果。烷基化产物在没有LiCl的情况下以94%的收率和93%的ee得到。(2)多取代苯是天然存在的生物活性分子的常见结构成分。两种或三种不同单炔的区域选择性环三聚是制备多取代苯的新且有效的途径。然而，控制区域选择性可能很困难。在催化量的[Ir(cod)Cl]_2和FDPPE存在下，丙炔酸甲酯与2分子1-炔反应以高收率得到3, 5-二取代苯甲酸酯。乙炔基对甲苯磺酸与各种1-炔烃反应高产率地得到相应的产物