1,3,5,7-Tetra(Bpin)azulene by Exhaustive Direct Borylation of Azulene and 5,7-Di(Bpin)azulene by Selective Subsequent Deborylation
1,3,5,7-Tetra(Bpin)azulene by Exhaustive Direct Borylation of Azulene and 5,7-Di(Bpin)azulene by Selective Subsequent Deborylation
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DOI：
10.1055/s-0034-1380686
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发表时间：
2015-07-01
期刊：
影响因子：
2
通讯作者：
Scott, Lawrence T.
中科院分区：
文献类型：
--
作者：
Nishimura, Hidetaka;Eliseeva, Maria N.;Scott, Lawrence T.
在促进硼基化的甘菊环平衡的条件下，用过量的双（频哪醇合）-二硼（B（2）pin（2））对甘菊环进行彻底硼基化，提供了作为主要产物的1，3，5，7-四（Bpin）甘菊环的方便的一步合成。1，3，5，7-四-（Bpin）奥林在室温下用三氟乙酸处理，可以方便地除去1和3位上的Bpin取代基，得到5，7-二（Bpin）奥林。5，7-二（Bpin）甘菊环作为5，7-二取代甘菊环的合成前体的效用通过Suzuki偶联得到先前未知的5，7-二苯基甘菊环而得到证明，否则难以获得。
Exhaustive borylation of azulene with excess bis(pinacolato)-diboron (B(2)pin(2)) under conditions that promote equilibration of the borylated azulenes provides a convenient one-step synthesis of 1,3,5,7-tetra(Bpin)azulene as the major product. The Bpin substituents at positions 1 and 3 can be conveniently removed from 1,3,5,7-tetra-(Bpin)azulene by treatment with trifluoroacetic acid at room temperature to give 5,7-di(Bpin)azulene. The utility of 5,7-di(Bpin)azulene as a synthetic precursor to 5,7-disubstituted azulenes that are otherwise difficult to access is demonstrated by Suzuki coupling to give the previously unknown 5,7-diphenylazulene.