Synthesis of 4,4′-biquinazoline alcohols as chiral catalysts in enantioselective alkynylation of aldehydes with phenyl acetylene
作者:Mustafa Catir、Murat Cakici、Semistan Karabuga、Sabri Ulukanli、Ertan Şahin、Hamdullah Kilic
DOI:10.1016/j.tetasy.2009.12.002
日期:2009.12
propargylic alcohols are important chiral-building blocks in asymmetric synthesis, while the asymmetric addition of a terminal alkyne to an aldehyde is one of the most important procedures to prepare these chiral-building blocks. In this work, a family of chiral 4,4′-biquinazoline alcohols has been conveniently prepared from the easily accessible (S)-2-acetoxycarboxylic acid chlorides by reaction sequences
光学活性的炔丙醇是不对称合成中的重要手性结构单元,而末端炔烃不对称加成到醛中是制备这些手性结构单元的最重要方法之一。在这项工作中,通过反应顺序,从缩合反应开始,然后进行关键的合成步骤,包括氯化,镍(0),这是很容易从易于获得的(S)-2-乙酰氧基羧酸氯化物制备的手性4,4'-联喹唑啉醇家族介导的均偶联和脱保护作用,此外还考虑了将苯基乙炔对醛进行对映选择性加成时可能的配体。这些手性配体可以与Ti(O i Pr)4结合然后用于催化由乙炔与二乙基锌反应原位生成的乙炔锌不对称加成到醛中。在这项研究中获得的最佳对映体过量为75%。