1255772-37-2Relevant academic research and scientific papers
Highly efficient Ir-catalyzed asymmetric hydrogenation of benzoxazinones and derivatives with a Br?nsted acid cocatalyst
Han, Zhengyu,Liu, Gang,Wang, Rui,Dong, Xiu-Qin,Zhang, Xumu
, p. 4328 - 4333 (2019)
The Ir-catalyzed highly efficient asymmetric hydrogenation of benzoxazinones and derivatives was successfully developed with N-methylated ZhaoPhos L5 as the ligand, which may display a new activation mode with a single anion-binding interaction among the
Exploration of chiral diastereomeric spiroketal (SPIROL)-based phosphinite ligands in asymmetric hydrogenation of heterocycles
Sun, Siyuan,Nagorny, Pavel
supporting information, p. 8432 - 8435 (2020/08/13)
New and readily available chiral SPIROL-based diphosphinite ligands (SPIRAPO) have been prepared and employed for iridium-catalyzed asymmetric hydrogenations of quinolines, quinoxalines and 2H-1,4-bezoxazin-2-ones. While the structurally similar (R,R,R)-SPIRAPO and (R)-SPINOL-based phosphinites were not the best ligands for these transformations, the (S,R,R)-diastereomer of SPIRAPO was found to be highly effective ligand for the reduction of 20 different heterocyclic systems with loadings as low as S/C = 10?000. This dearomatizative hydrogenation provided direct access to optically active tetrahydroquinolines in high enantioselectivities (up to 94percent ee) and excellent yields (up to 99percent), and was used to generate 1.75 g of natural alkaloid (-)-(R)-angustureine. This protocol was subsequently extended to achieve asymmetric hydrogenation of quinoxalines and 2H-1,4-benzoxazin-2-ones in good to excellent enantioselectivities.
Biomimetic asymmetric hydrogenation: In situ regenerable Hantzsch esters for asymmetric hydrogenation of benzoxazinones
Chen, Qing-An,Chen, Mu-Wang,Yu, Chang-Bin,Shi, Lei,Wang, Duo-Sheng,Yang, Yan,Zhou, Yong-Gui
supporting information; experimental part, p. 16432 - 16435 (2011/12/04)
A catalytic amount of Hantzsch ester that could be regenerated in situ by Ru complexes under hydrogen gas has been employed in the biomimetic asymmetric hydrogenation of benzoxazinones with up to 99% ee in the presence of chiral phosphoric acid. The use of hydrogen gas as a reductant for the regeneration of Hantzsch esters makes this hydrogenation an ideal atom economic process.
