Synthesis of a Novel Enantiopure Spiro-B-norestradiol Analogue by Multiple Pd-Catalyzed Transformations
作者:Lutz F. Tietze、J. Matthias Wiegand、Carsten A. Vock
DOI:10.1002/ejoc.200400263
日期:2004.10
The novel tetracyclic spiro compound 13 was synthesized by the use of two subsequent Pd-catalyzed reactions. Firstly, the ortho-bromobenzyl chloride 1 was coupled with the enantiopure boronic ester 8, obtained from the Hajos−Wiechert ketone in a chemoselective Suzuki-type reaction to give 12 in 77% yield. Unexpectedly, the intramolecular Heck reaction then did not provide the annulated compound 6,
通过使用两个后续的 Pd 催化反应合成了新型四环螺环化合物 13。首先,邻溴苄基氯 1 与从 Hajos-Wiechert 酮中获得的对映纯硼酸酯 8 偶联,在化学选择性 Suzuki 型反应中得到 12,产率为 77%。出乎意料的是,分子内 Heck 反应没有提供环状化合物 6,而是提供含有季碳中心的螺环化合物 13,产率为 73%。Heck 反应也在微波辐射条件下进行,可以显着缩短反应时间。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)