作者:Yoshiaki Kato、Kenji Niiyama、Takayuki Nemoto、Hideki Jona、Atsushi Akao、Shigemitsu Okada、Zhiguo J Song、Matthew Zhao、Yoshimi Tsuchiya、Koji Tomimoto、Toshiaki Mase
DOI:10.1016/s0040-4020(02)00280-6
日期:2002.4
An asymmetric synthesis of a selective endothelin A receptor antagonist 1b is described. A highly substituted pyridine intermediate 11a was efficiently prepared via a mono-amination of inexpensive 2,6-dichloropyridine followed by a Vilsmeier formylation. Asymmetric conjugate addition of aryl lithium 14 to the chiral oxazoline 13 followed by hydrolysis afforded 15 in 90% ee. Pd(OAc)2/dppf catalyzed
描述了选择性内皮素A受体拮抗剂1b的不对称合成。通过廉价的2,6-二氯吡啶的单胺化,然后进行维尔斯迈尔甲酰化反应,可以有效地制备高度取代的吡啶中间体11a。将芳基锂14不对称地共轭添加到手性恶唑啉13中,然后水解,得到15的90%ee。Pd(OAc)2 / dppf催化的羰基化反应,然后化学选择性地添加芳基锂18,得到酮19。非对映选择性还原LS-Selectride酮®随后伴随着所得到的醇的活化和环化作用,产生了较晚的中间体21。通过结晶脱保护和纯化,提供对映体纯的目标分子1b,其来自11a的总产率为10%。