The present invention is a photochromic material formed of a biimidazole compound represented by general formula (1-1):
(where, R
4
and R
5
respectively and independently represent a halogen atom or alkyl group, R
1
to R
3
and R
6
to R
8
respectively and independently represent a hydrogen atom, halogen atom, alkyl group, fluoroalkyl group, hydroxyl group, alkoxyl group, amino group, alkylamino group, carbonyl group, alkylcarbonyl group, nitro group, cyano group or aryl group, Ar
1
to Ar
4
respectively and independently represent a substituted or unsubstituted aryl group, R
4
may form a condensed, substituted or unsubstituted aryl ring with R
3
, and R
5
may form a condensed, substituted or unsubstituted aryl ring with R
6
).
Synthesis of Axially Chiral Biaryls via Enantioselective Ullmann Coupling of
<i>ortho</i>
‐Chlorinated Aryl Aldehydes Enabled by a Chiral 2,2′‐Bipyridine Ligand
作者:Saima Perveen、Shuai Zhang、Linghua Wang、Peidong Song、Yizhao Ouyang、Jiao Jiao、Xin‐Hua Duan、Pengfei Li
DOI:10.1002/anie.202212108
日期:2022.11.21
Reported is a general and highlyenantioselective Ni-catalyzed reductive homocoupling of ortho-chlorinated aldehydes enabled by a SBpy-type chiral 2,2′-bipyridine ligand. This mild and step-economical approach allowed the synthesis of various axiallychiral biaryl dials, and also provided versatile intermediates for diverse axiallychiral catalysts, ligands, and natural products.
报道了由 SBpy 型手性 2,2'-联吡啶配体实现的一般且高度对映选择性的 Ni 催化的邻氯代醛的还原自偶联。这种温和且步骤经济的方法允许合成各种轴向手性联芳基表盘,并为各种轴向手性催化剂、配体和天然产物提供多功能中间体。