排序方式: 共有93条查询结果,搜索用时 15 毫秒
41.
42.
Dipl.‐Chem. Matthias Müller Dr. Cäcilia Maichle‐Mössmer Prof. Dr. Holger F. Bettinger 《Angewandte Chemie (International ed. in English)》2014,53(35):9380-9383
Thermolysis of 9‐azido‐9‐borafluorene in heptane solution produces the tetramer of a BN‐phenanthryne. The isolation of the self‐trapping product provides evidence for the involvement of the BN‐aryne in the thermolysis reaction. Its formation may be rationalized by denitrogenation of the azide and ring enlargement. 相似文献
43.
Using (phenyl)[2‐(trimethylsilyl)phenyl]iodonium triflate as a precursor of arynes, Larock's method for O‐arylation of carboxylic acids and arynes was developed. A variety of acids including simple aliphatic carboxylic acids, aromatic carboxylic acids, allenoic acids, and p‐toluenesulfonic acid under mild reaction conditions could generate the aryl esters. 相似文献
44.
45.
46.
47.
Dr. Takashi Ikawa Dr. Shigeaki Masuda Prof. Shuji Akai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(19):4320-4332
Benzynes were selectively generated in situ from phenols and trapped regioselectively with potassium hexamethyldisilazide to form primary anilines following acidic workup. The direct conversion of a phenolic hydroxyl group into a free amino group is a useful method for the preparation of primary aryl amines that are hard to synthesize by using coupling reactions involving phenol derivatives with ammonia. Whereas reactions of ortho- and meta-substituted phenols produced meta-substituted anilines exclusively, those of para-substituted phenols provided ortho-silylanilines. 相似文献
48.
Dr. Nurbey Gulia Jarosław Fornalski Adrianna Gumienna Małgorzata Ambroziak Prof. Dr. Sławomir Szafert 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(66):e202202449
A method of palladium-catalyzed C−H arylation assisted with a 3,4,4-trimethylpyrazol-5-on directing group, selectively providing mono- and di-ortho-arylated products is reported. Steric hindrance appearing between the directing group and the already introduced aryl substituent enables control of mono- vs. diarylation selectivity by the temperature of the reaction. Taking advantage of this, a series of monosubstituted and disubstituted derivatives were obtained in good yields. Moreover, unsymmetrical double-arylation in a one-pot procedure was developed to give corresponding products in reasonable yields. Additionally, synthesis and X-ray study of intermediate palladium metallacycles of both, the first and second arylation reactions, were conducted. X-ray structure comparison emphasizes the geometrical differences that were consistent with the observed reactivity. Finally, decarboxylative cleavage of the pyrazolone directing group under mild conditions gave synthetically useful hydrazones. The presented solution opens the alternative synthetic way to such ortho arylated derivatives of arylhydrazines. 相似文献
49.
50.