Bedford-Type Palladacycle-Catalyzed Miyaura Borylation of Aryl Halides with Tetrahydroxydiboron in Water
摘要:
A mild aqueous protocol for palladium catalyzed Miyaura borylation of aryl iodides, aryl bromides and aryl chlorides with tetrahydroxydiboron (BBA) as a borylating agent is developed. The developed methodology requires low catalyst loading of Bedford-type palladacycle catalyst (0.05 mol %) and works best under mild reaction conditions at 40 degrees C in short time of 6 h in water. In addition, our studies show that for Miyaura borylation using BBA in aqueous condition, maintaining a neutral reaction pH is very important for reproducibility and higher yields of corresponding borylated products. Moreover, our protocol is applicable for a broad range of aryl halides, corresponding borylated products are obtained in excellent yields up to 93% with 29 examples demonstrating its broad utility and functional group tolerance.
positive CN ion and the corresponding directcyanation are both extremely important for cyanation of aromatic compounds. Hereby, we would like to report the simultaneous use of the new Pd nano-catalyst as well as the three types of the N-arylsulfonyl cyanamides (A, B and C) as potent reagents for the in situ generation of the positive CN ion for the directcyanation of phenylboronic acids in acetonitrile
Experimental and Computational Studies on the Directing Ability of Chalcogenoethers in Palladium‐Catalyzed Atroposelective C−H Olefination and Allylation
作者:Gang Liao、Tao Zhang、Liang Jin、Bing‐Jie Wang、Cheng‐Kai Xu、Yu Lan、Yu Zhao、Bing‐Feng Shi
DOI:10.1002/anie.202115221
日期:2022.3
of chalcogenoether motifs in Pd-catalyzed atroposelective C−Holefination and allylation are presented. The thioether motif was found to be a superior directing group compared to the corresponding ether (−OR) and selenoether in terms of reactivity and enantiocontrol. The selenoether unit (−SeMe) was used for the first time as a suitable directing group in asymmetric C−H activation.