Development of Transition-Metal-Catalyzed Reactions of Preparing Allenes and Their Derivatives

在此之前，我们报道了钯催化的2-溴-1,3-二烯的反应，这种反应很容易从各种醛中得到，软亲核试剂得到功能化的烯。用手性钯催化剂将反应扩展为不对称反应，得到了具有良好对映选择性的轴向手性烯。发现烯丙基硅烷可以制备类似溴二烯的底物。结果表明，1,3-二烯-2-y1三氟乙烯酸酯在pd催化反应中表现出与溴二烯相似的反应活性，该酯容易由乙烯基酮以高收率制备。这提供了一个途径，以获得多取代的烯，这是无法从醛的途径。将pd催化的烯合成反应应用于雄性干豆甲虫性信息素的不对称全合成。在pd催化的不对称轴手性烯的合成中，联芳基双膦类化合物（如binap）具有较高的对映选择性。研究发现，在联芳基骨架的3′和3′位置引入体积较大的取代基，提高了联芳基手性膦在pd催化反应中的性能。分离了pd催化反应的中间产物烷基烯-π-烯丙基钯，并对其溶液动力学进行了研究。在此基础上，建立了2-溴-1,3,5-三烯与软亲核试剂共轭乙烯烯的新反应。该反应成功地扩展为不对称反应。已知偶联炔的1,4-硅氢化反应可得到烯基硅烷。将新开发的手性磷二茂铁应用于烯烃的不对称硅氢化反应，得到了具有良好对映选择性的轴向手性烯基硅烷。在铜(I)盐存在的情况下，用丙炔亲电试剂处理适当的锆环戊烷类得到立体定向的双烯产物。

Previously, we reported a palladium-catalyzed reaction of 2-bromo-1,3-dienes, which could be easily derived from a variety of aldehydes, with soft nucleophiles giving functionalized allenes. The reaction was extended to an asymmetric counterpart by using a chiral palladium catalyst and the corresponding axially chiral allenes were obtained with excellent enantioselectivity.It was found analogous bromodiene substrates could be prepared from allylsilanes. It was demonstrated that 1,3-dien-2-y1 triflates, which were easily obtained in high yields from vinylketones, showed analogous reactivity to the bromodienes in the Pd-catalyzed reaction. These provided a route to multi-substituted allenes, which were inaccessible by the route from aldehydes.The Pd-catalyzed allene synthesis reaction was applied to asymmetric total synthesis of the sex pheromone of male dried bean beetle.For the Pd-catalyzed asymmetric synthesis of the axially chiral allenes, biaryl bisphosphines, such as binap, were effective for high enantioselectivity. It was found that introduction of bulky substituents at the 3-and 3'-positions of the biaryl skeleton improved the performance of the biaryl chiral phosphines in the Pd-catalyzed reaction.An intermediate of the Pd-catalyzed reaction, alkylidene-π-allylpalladium species, was isolated and its solution dynamics was studied. Based on the results, a novel reaction of 2-bromo-1,3,5-trienes with soft nucleophiles giving conjugated vinylallenes was developed. The reaction was successfully extended to the asymmetric reaction.It was known that 1,4-hydrosilylation of conjugated enynes afforded allenylsilanes. Newly developed chiral phosphaferrocenes were applied to the asymmetric hydrosilylation of enynes and axially chiral allenylsilanes were obtained with excellent enantioselectivity.Treatment of appropriate zirconacyclopentane species with propargyl electrophiles in the presence of copper(I) salts gave bis-allene products in a stereospecific fashion.