Practical, general, and systematic method for optical resolution of gem-dihalo- and monohalocyclopropanecarboxylic acids utilizing chiral 1,1′-binaphtholmonomethyl ethers: Application to the synthesis of three chiral pesticides
作者:Hiroaki Yasukochi、Takayuki Atago、Akihiro Tanaka、Hidefumi Nakatsuji、Eri Yoshida、Akikazu Kakehi、Yoshinori Nishii、Yoo Tanabe
DOI:10.1039/b714614k
日期:——
We performed an efficient practical and systematic optical resolution method for gem-dihalo- and monohalocyclopropanecarboxylic acids and utilizing chiral 1,1'-binaphthol monomethyl ether (R)- as the key auxiliary. Direct esterification of with (R)- gave two 1R- and 1S-diastereomeric esters with marked different R(f) values, both of which were easily separated using simple column chromatography. Monodehalogenation
我们对宝石二卤代和单卤代环丙烷羧酸进行了有效的实用且系统的光学拆分方法,并利用手性1,1'-联萘酚单甲醚(R)-作为关键助剂。用(R)-直接酯化可得到两种R(f)值明显不同的1R-和1S-非对映体酯,使用简单的柱色谱法即可轻松分离这两种酯。使用t-BuMgCl和催化剂对分离的手性酯进行单脱卤。Co(dppe)(2)Cl(2)给出了两个R(f)值明显不同的1,2-反式和1,2-顺式非对映异构体,使用简单的柱色谱法对两者进行了相似的分离。所获得的非对映异构体容易被水解成所需的对映纯酸(> 99%)和(> 99%),同时回收(R)-,均具有良好的收率和优异的收率。利用本发明的方法,很容易合成重要的手性农用化学品,杀虫剂和丙环酸。与报道的方法相比,具有三个不对称中心的拟除虫菊酯可以高效合成,产率更高。