C(sp
<sup>3</sup>
)–H methylation enabled by peroxide photosensitization and Ni-mediated radical coupling
作者:Aristidis Vasilopoulos、Shane W. Krska、Shannon S. Stahl
DOI:10.1126/science.abh2623
日期:2021.4.23
candidate associated with addition of a single methyl group. We report a synthetic method that enables direct methylation of C(sp3)–H bonds in diverse drug-like molecules and pharmaceutical building blocks. Visible light–initiated triplet energy transfer promotes homolysis of the O–O bond in di-tert-butyl or dicumyl peroxide undermildconditions. The resulting alkoxyl radicals undergo divergent reactivity
Iridium Catalysts with Chiral Imidazole-Phosphine Ligands for Asymmetric Hydrogenation of Vinyl Fluorides and other Olefins
作者:Päivi Kaukoranta、Mattias Engman、Christian Hedberg、Jonas Bergquist、Pher G. Andersson
DOI:10.1002/adsc.200800062
日期:2008.5.5
New chiral bidentate imidazole-phosphine ligands have been prepared and evaluated for the iridium-catalysed asymmetric hydrogenation of olefins. The imidazole-phosphine-ligated iridiumcatalysts hydrogenated trisubstituted olefins with the same sense of enantiodiscrimination as known iridiumcatalysts possessing oxazole and thiazole as N-donors. The imidazole-based catalysts were shown to hydrogenate
Alkylation of Benzene with Optically Active 3-Chloro-1-butanol, 3-Chlorobutanoic Acid, and Their Esters
作者:Tadashi Nakajima、Shinji Masuda、Satoru Nakashima、Takayuki Kondo、Yoshiaki Nakamoto、Sohei Suga
DOI:10.1246/bcsj.52.2377
日期:1979.8
The alkylations of benzene with opticallyactive 3-chloro-1-butanol, 3-chlorobutanoic acid and their esters in the presence of aluminium chloride gave the corresponding 3-phenyl substituted derivatives in good optical yield. All these reactions were found to proceed with inversion of configuration at the attacking carbon atom. The products were not racemized under the conditions used, while the starting
Optically active benzene derivatives, process for producing the same and
申请人:Sumitomo Chemical Company, Limited
公开号:US05389293A1
公开(公告)日:1995-02-14
Disclosed are herein optically active benzene derivatives represented by the formula (I): ##STR1## preparation processes therefor, liquid crystal composition containing such benzene derivatives as liquid-crystalline compound, and a light switching element using said liquid crystal composition as liquid crystal element, wherein R.sub.1, R.sub.2, x, y, z, m, p and s are as defined in the specification.
Novel optically active benzene derivatives, process for producing the same and liquid-crystalline composition containing said derivatives as liquid-crystalline compound and light switching elements
申请人:SUMITOMO CHEMICAL COMPANY, LIMITED
公开号:EP0360622A2
公开(公告)日:1990-03-28
Disclosed are herein optically active benzene derivatives represented by the formula (I):
(wherein R1 represents an alkyl group having 3 to 20 carbon atoms; Y represents -0-, -COO- or -OCO-; m, p and s each represents a number of 0 or 1; Ar represents
provided that when p is 1 Ar represents
when p is 0 Ar represents
X represents -COO- or -OCO-; Z represents
wherein q represents a number of 1 to 5, t represents a number of 0 to 5, ℓ represents a number of 1 or 2, u represents a number of 0 or 1 and indicates asymmetric carbon atom; provided that when Ar represents
Z represents
when P is 0 Z represents
with the proviso that when t is 0 Ar represents
R2 represents an alkyl or alkoxyalkyl group having 1 to 20 carbon atoms optionally substituted by halogen atoms; provided that when u is 0, R2 represents an optically active alkyl or alkoxyalkyi group having 1 to 20 carbon atoms optionally substituted by halogen atoms), preparation processes therefor, liquid crystal composition containing such benzene derivatives as liquid-crystalline compound, and a light switching element using said liquid crystal composition as liquid crystal element.
本文公开了由式(I)代表的光学活性苯衍生物:
(其中 R1 代表具有 3 至 20 个碳原子的烷基;Y 代表 -0-、-COO- 或 -OCO-;m、p 和 s 各代表 0 或 1;Ar 代表
但当 p 为 1 时,Ar 代表
当 p 为 0 时,Ar 代表
X 代表-COO-或-OCO-; Z 代表
其中 q 代表 1 至 5 的数字,t 代表 0 至 5 的数字,ℓ 代表 1 或 2 的数字,u 代表 0 或 1 的数字,并表示不对称碳原子;条件是当 Ar 代表
Z 代表
当 P 为 0 时,Z 代表
但当 t 为 0 时,Ar 代表
R2 代表具有 1 至 20 个碳原子、可任选被卤素原子取代的烷基或烷氧基烷基;但当 u 为 0 时,R2 代表具有 1 至 20 个碳原子、可任选被卤素原子取代的光学活性烷基或烷氧基烷基)、其制备工艺、含有此类苯衍生物作为液晶化合物的液晶组合物,以及使用所述液晶组合物作为液晶元件的光开关元件。