Di-(−)-(1R,2S)-2-phenyl-1-cyclohexyl Diazenedicarboxylate

Abstract

[206359-91-3] C26H30N2O4 (MW 434.53(E)) InChI = 1S/C26H30N2O4/c29-25(31-23-17-9-7-15-21(23)19-11-3-1-4-12-19)27-28-26(30)32-24-18-10-8-16-22(24)20-13-5-2-6-14-20/h1-6,11-14,21-24H,7-10,15-18H2/b28-27+/t21-,22-,23+,24+/m0/s1 InChIKey = RHBWBKFUCXVAMA-KQEKZTIUSA-N (reagent used as a chiral azo-enophile in asymmetric azo-ene reactions) Alternate Name: (1R-{1α[E(1R*,2S*)],2β})-Bis(2-phenylcyclohexyl) diazenedicarboxylate. Physical Data: [α]D −56.9 (c 0.65, CHCl3). Solubility: soluble in CH2Cl2, diethyl ether, and most organic solvents. Form Supplied in: yellow oil. Analysis of Reagent Purity: 1H NMR, IR, TLC, elemental analysis. Preparative Methods: The title reagent is prepared1 by reaction of (1R, 2S)-2-phenyl-1-cyclohexanol with excess phosgene in the presence of quinoline to afford a chloroformate which is treated directly with hydrazine monohydrate (0.5 equiv) to afford di-(−)-(1R, 2S)-2-phenyl-1-cyclohexyl diazanedicarboxylate. Oxidation of the diazanedicarboxylate to the diazenedicarboxylate is then readily effected using N-bromosuccinimide and pyridine (eq 1). (1) Purification: flash chromatography using hexaneethyl acetate (9:1) as eluent. Handling, Storage, and Precautions: store in closed vessels under an inert atmosphere in the refrigerator. Protect from light.