75-22-9Relevant articles and documents
Rhodium-Catalyzed B-H Bond Insertion Reactions of Unstabilized Diazo Compounds Generated in Situ from Tosylhydrazones
Pang, Yue,He, Qiao,Li, Zi-Qi,Yang, Ji-Min,Yu, Jin-Han,Zhu, Shou-Fei,Zhou, Qi-Lin
supporting information, p. 10663 - 10668 (2018/09/06)
Although transition-metal-catalyzed B-H bond insertion of carbenes into stable borane adducts has emerged as a promising method for organoborane synthesis, all the diazo compounds used to date as carbene precursors have had an electron-withdrawing group to stabilize them. Herein, we report a protocol for rhodium-catalyzed B-H bond insertion reactions of unstabilized diazo compounds generated in situ from tosylhydrazones. In addition, by using chiral dirhodium catalysts, we also achieved an asymmetric version of the reaction with good to excellent enantioselectivities (up to 98:2 e.r.). This is the first enantioselective heteroatom-hydrogen bond insertion reaction to use unstabilized diazo compounds as carbene precursors. The protocol exhibited good functional group tolerance and could be carried out on a gram scale. It also enabled one-pot transformation of a carbonyl group to a boryl group enantioselectively. The B-H bond insertion products could be easily transformed into chiral alcohols and other widely used organoboron reagents with enantiomeric fidelity.
Amine-boranes bearing borane-incompatible functionalities: Application to selective amine protection and surface functionalization
Veeraraghavan Ramachandran,Kulkarni, Ameya S.,Zhao, Yan,Mei, Jianguo
supporting information, p. 11885 - 11888 (2016/10/09)
The first general open-flask synthesis of amine-boranes with inexpensive and readily available reagents, such as sodium borohydride, sodium bicarbonate, water, and the desired amines is described. Even amines bearing borane-reactive functionalities, such as alkene, alkyne, hydroxyl, thiol, ester, amide, nitrile, and nitro are well tolerated. Some of these novel amine-boranes represent stable molecules containing potentially incompatible electrophilic and nucleophilic centers in proximity. This convenient scalable synthesis provides a novel class of organic ligands for surface functionalization, as demonstrated by the formation of self-assembled layers of thiol- and alkoxysilane-bearing amine-boranes on gold and silica surfaces, respectively.
Electrophilic C-H borylation and related reactions of B-H boron cations
Prokofjevs, Aleksandrs,Jermaks, Janis,Borovika, Alina,Kampf, Jeff W.,Vedejs, Edwin
, p. 6701 - 6711 (2014/01/06)
Catalytic procedures are described for the amine-directed borylation of aliphatic and aromatic tertiary amine-boranes. Sequential double borylation is observed in cases where two or more C-H bonds are available that allow 5-center or 6-center intramolecular borylation. The HNTf2-catalyzed borylation of benzylamine-boranes provides a practical means for the synthesis of ortho-substituted arylboronic acid derivatives, suitable for Suzuki-Miyaura cross-coupling applications.