Palladium(II)-Catalyzed 1,4-Addition of Arylboronic Acids to β-Arylenones for Enantioselective Synthesis of 4-Aryl-4H-chromenes
作者:Takashi Nishikata、Yasunori Yamamoto、Norio Miyaura
DOI:10.1002/adsc.200600622
日期:2007.7.2
carried out at 0–25 °C in the presence of a dicationic palladium(II) catalyst, [Pd(S,S-chiraphos)(PhCN)2](SbF6)2. Addition of a silver salt such as silver tetrafluoroborate [AgBF4] or silver hexafluoroantimonate [AgSbF6] (5–10 mol %) was effective to achieve high enantioselectivities at low temperatures (92–99 % ee) and to reduce the catalyst loading to 0.05 mol %. The protocol provided a simple access to
在阳离子钯(II)催化剂[Pd(S,S -chiraphos)存在下,在0–25°C的条件下将芳基硼酸与β-芳烯酮进行对映选择性的1,4-加成反应,得到β-二芳基酮。(PhCN)2 ](SbF 6)2。添加银盐,例如四氟硼酸银[AgBF 4 ]或六氟锑酸银[AgSbF 6 ](5-10 mol%),可以有效地在低温下(92-99%ee)实现高对映选择性,并降低催化剂的负载量。 0.05摩尔%。该协议提供了对4-芳基-4 H-色烯的简单访问。旋光色烯可通过高达99%的ee合成。 芳基硼酸和β-(2-羟基芳基)-α,β-不饱和酮之间的1,4-加合物的脱水反应