Iridium-catalyzed highly selective reactions

我们研究了下列反应。(1)不对称烯丙基烷基化是通过非手性底物的碳-碳成键反应构建新的手性中心的最有力工具之一。一个具有挑战性的课题，在这个领域是区域和对映选择性烯丙基烷基化的不对称底物。手性磷酰胺配体在过渡金属不对称合成中占有重要地位。Helmchen首先使用联萘酚基磷酰胺进行铱催化的对映选择性烯丙基烷基化。设计了一种新型磷酰胺P(OR)_2（酰胺）配体。酰胺基的平面性极大地促进了更刚性的手性空间。此外，这种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成为手性双齿配体。在2mol %的[Ir(cod)Cl]_2和4mol %的配体存在的情况下，研究了乙酸肉桂酰与二丙二酸钠的反应效率。以含恶唑烷酮的配体为最佳配体。在不添加LiCl的情况下，得到了收率为94%、ee为93%的烷基化产物。(2)聚取代苯是天然存在的生物活性分子的常见结构成分。两种或三种不同单体的区域选择性环三聚化反应是制备多取代苯的有效新途径。然而，区域选择性很难控制。在[Ir(cod)Cl]_2和FDPPE的催化作用下，丙酸甲酯与2分子1-炔反应得到高产率的3,5 -二取代苯甲酸酯。对甲基乙基砜与多种1-炔反应，产率高

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