Kinetic resolution of azaflavanonesviaa RuPHOX-Ru catalyzed asymmetric hydrogenation

Abstract

The kinetic resolution of azaflavanones has been established via RuPHOX-Ru catalyzed asymmetric hydrogenation, providing chiral azaflavanones and azaflavanols in high yields with up to >20:1 dr and 99.7% ee. The...

Ru-Catalyzed Asymmetric Addition of Arylboronic Acids to Aliphatic Aldehydes via P-Chiral Monophosphorous Ligands

“…Reactions were carried out under a nitrogen atmosphere. 1 H and 13 C NMR spectra were recorded using a 400 MHz NMR spectrometer (CDCl 3 , δ H = 7.26 ppm, δ C = 77.23 ppm). The melting point was determined by a WRR melting point apparatus.…”

“…Yield: 97% (130.2 mg) as a yellow oil; 1 H NMR (400 MHz, CDCl 3 ) δ 7.54-6.94 (m, 9H), 4.63 (dd, J = 7.9, 5.4, 1H), 2.99-2.54 (m, 2H), 2.25-1.98 (m, 2H), 1.95 (s, 1H) and 1.31 (s, 9H). 13 C NMR (100 MHz, CDCl 3 ) δ 150. 64, 141.94, 141.62, 128.50, 128.41, 125.85, 125.74, 125.46, 73.71, 40.32, 34.58, 32.18 and 31.42.…”

“…Yield: 45% (60.7 mg) as a yellow oil; 1 H NMR (400 MHz, CDCl 3 ) δ 7.53-7.03 (m, 7H), 6.86 (d, J = 8.3, 2H), 4.61 (dd, J = 6.7, 1H), 4.53 (p, J = 6.0, 1H), 2.78-2.57 (m, 2H), 2.19-1.93 (m, 2H), 1.87 (s, 1H) and 1.33 (d, J = 6.0, 6H). 13 C NMR (100 MHz, CDCl 3 ) δ 157. 45, 141.90, 136.51, 128.47, 128.39, 127.25, 125.83, 115.86, 73.55, 69.95, 40.32, 32.17 1-(4-chlorophenyl)-3-phenylpropan-1-ol (3ae) [87] [a] 20 D = +13.1 (c 1.17, CH 2 Cl 2 ).…”

“…Yield:91% (132.4 mg) as a yellow oil; 1 H NMR (400 MHz, CDCl 3 ) δ 7.44 (d, J = 7.9, 2H), 7.35-7.03 (m, 7H), 4.59 (dd, J = 6.6, 1H), 2.75-2.56 (m, 2H), 2.12 (s, 1H) and 2.08-1.89 (m, 2H). 13 C NMR (100 MHz, CDCl 3 ) δ 143. 58, 141.51, 131.62, 128.50, 128.46, 127.71, 126.02, 121.37, 73.18, 40.47 and 31.93.…”

“…Thus, the invention of methods for the preparing of such chiral aryl alkyl alcohols features an important role in organic synthesis. Classic methods for constructing such chiral molecules include asymmetric hydrogenation of ketones [11][12][13], asymmetric hydrogen transfer reduction of ketones or unsaturated ketones [14][15][16][17][18][19][20][21], along with the asymmetric addition of organometallic reagents to aldehydes [22][23][24]. As an alternative, strategies via the asymmetric homologation reaction [25][26][27][28], tandem Michael-MPV reaction and subsequent reductive desulfurization [29], as well as the asymmetric addition of aldehydes with arylboronic acids were also established [30,31].…”