Development of an Azanoradamantane-Type Nitroxyl Radical Catalyst for Class-Selective Oxidation of Alcohols

Abstract

The development of 1,5-dimethyl-9-azanoradamantane N-oxyl (DMN-AZADO; 1,5-dimethyl-Nor-AZADO, 2) as an efficient catalyst for the selective oxidation of primary alcohols in the presence of secondary alcohols is described. The compact and rigid structure of the azanoradamantane nucleus confers potent catalytic ability to DMN-AZADO (2). A variety of hindered primary alcohols such as neopentyl primary alcohols were efficiently oxidized by DMN-AZADO (2) to the corresponding aldehydes, whereas secondary alcohols remained intact. DMN-AZADO (2) also has high catalytic efficiency for one-pot oxidation from primary alcohols to the corresponding carboxylic acids in the presence of secondary alcohols and for oxidative lactonization from diols.

Formal total synthesis of histrionicotoxin alkaloids via Hg(OTf)2-catalyzed cycloisomerization and SmI2-induced ring expansion

“….61-1.53 (0.8H, m), 1.52-1.38 (2H, m), 1.38 and 1.36 (total 9H, each s), 1.03 (9H, s); 13 C-NMR (150 MHz, CDCl 3 , 25 C, two rotamers in a 4 : 1 ratio) d 210. 9, 210.0, 153.3, 152.9, 138.5, 138.2, 135.49, 135.45, 134.1, 133.9, 133.84, 133.82, 129.43, 129.42, 129.36, 129.3, 128.3, 128.2, 127.6, 127.5, 127.4, 127.3, 80.2, 79.4, 73.0, 71.2, 70.8, 70.3, 69.4, 63.2, 62.8, 59.7, 59.1, 54.3, 52.4, 42.0, 41.8, 37.7, 36.8, 33.7, 32.4, 28.5, 28.4, 27.0, 26.84, 26.80, 26.6, 26.3, 25.8, 21.5, 19.1;IR (ATR) 3070, 3048, 3032, 2956, 2929, 2858, 1712, 1688, 1589, 1541, 1472, 1455, 1428, 1388, 1364, 1317, 1298, 1254, 1219, 1171, 1111, 1072, 1029 13 C-NMR (150 MHz, CDCl 3 , 25 C, two rotamers in a 5 : 1 ratio) d 210. 5, 209.5, 153.2, 152.9, 138.3, 138.1, 135.54, 135.52, 134.13, 134.10, 134.07, 133.9, 129.6, 129.4, 128.4, 128.3, 127.7, 127.64, 127.59, 127.53, 127.50, 80.2, 79.6, 73.2, 71.0, 70.7, 70.5, 70.4, 62.83, 62.75, 58.2, 57.8, 52.4, 52.1, 41.5, 41.4, 32.2, 30.6, 28.4, 26.9, 26.8, 25.7, 25.3, 24.5, 23.…”

“…The residue was puried by ash column chromatography (EtOAc/hexane, 10 : 90) on silica gel to provide eq-12 (77.4 mg, 118 mmol, 58%) and ax-12 ( , m), 3.91 (0.67H, m), 3.77 (0.33H, dt, J ¼ 10.2, 4.1 Hz), 3.72-3.65 (0.67H, m), 3.61 (0.67H, td, J ¼ 10.0, 3.7 Hz), 3.57 (0.33H, m), 3.56 (0.33H, td, J ¼ 9.3, 2.5 Hz), 3.49 (0.67H, dd, J ¼ 8.9, 3.1 Hz), 3.45 (0.33H, dd, J ¼ 8.9, 7.7 Hz), 3.43-3.32 (1H, m), 3.29 (0.67H, t, J ¼ 8.5 Hz), 2.77 (0.67H, br t, J ¼ 7.4 Hz), 2.39 (0.67H, td, J ¼ 13.2, 4.2 Hz), 2.37 (0.33H, m), 2.16 (0.33H, td, J ¼ 12.9, 3.6 Hz), 2.10-1.99 (1H, m), 1.99-1.88 (1H, m), 1.88-1.53 (7H, m), 1.45-1.16 (2H, m), 1.38 (3H, s), 1.26 (6H, s), 1.07 (3H, s), 1.04 (6H, s); 13 C-NMR (150 MHz, CDCl 3 , 25 C, two rotamers in a 2 : 1 ratio) d 153.5, 152. 6, 138.6, 138.3, 135.64, 135.59, 135.56, 133.0, 132.6, 132.5, 129.94, 129.90, 129.72, 129.67, 128.4, 128.3, 127.8, 127.7, 127.6, 127.44, 127.39, 79.9, 79.0, 73.11, 73.06, 73.0, 71.5, 70.7, 68.9, 68.3, 65.1, 64.6, 59.0, 58.6, 50.0, 47.3, 37.9, 36.8, 35.1, 35.0, 33.4, 31.8, 31.4, 31.1, 28.5, 28.3, 26.8, 26.7, 26.0, 20.58, 20.56, 19.0, 18.9;IR (ATR) 3435, 3070, 3048, 3032, 2956, 2929, 2858, 1688, 1589, 1541, 1472, 1455, 1428, 1388, 1364, 1317, 1298, 1254, 1219, 1171, 1111, 1072, 1029 13 C-NMR (150 MHz, CDCl 3 , 25 C, two rotamers in a 3 : 1 ratio) d 153. 7, 152.8, 138.7, 138.4, 135.6, 135.5, 133.3, 133.2, 129.80, 129.78, 129.74, 129.71, 128.4, 128.3, 127.8, 127.73, 127.71, 127.6, 127.5, 127.4, 127.3, 79.5, 78.8, 73.02, 72.98, 71.3, 70.7, 68.9, 68.6, 67.1, 66.7, 63.7, 63.5, 58.5, 58.1, 43.1, 41.1, 39.3, 38.4, 34.2, 33.1, 33.0, 32.6, 29.3, 29.0, 28.6, 28.5, 26.9, 26.81, 26.79, 26.2, 19.03, 19.01, 18.7, 18.6;IR (ATR) 3485, 3070, 3049, 3031, 2957, 2929, 2858, 1673, 1473, 1454, 1428, 1388, 1364<...>…”

Development of New Synthetic Methods Using Oxiranyl Anions and Application in the Syntheses of Polycyclic Ether Marine Natural Products

“…An improved route to the KLMN fragment 162 from the FGH fragment 157 was also developed by taking advantage of the same structural motif of FGH and KLM ring systems. 84) 8.3. Completion of the Total Synthesis of Gymnocin-A In the coupling stage of the three fragments 140, 157, and 142, the order of assembly was designed to avoid the formation of the unstable triflate of a large polycyclic ether.…”

Maculatic Acids—Sex Attractant Pheromone Components of Bald‐Faced Hornets

“…Considering that the amount of analyte was insufficient to infer the olefin geometry by NMR analysis,w es elected af lexible synthetic route that would provide each of the four possible stereoisomers.A sd epicted in Figure 4, aH orner-Wadsworth-Emmons mono-olefination of 2,6-hexanedione [19] using tert-butyl-2-(dimethoxyphosphoryl)acetate afforded the esters 7 and 8 in 48 %combined yield, [20] which were separable by flash column chromatography using AgNO 3 -impregnated silica gel. With geometrically pure 7 and 8 in hand, as ubsequent Wittig reaction with the anion derived from (2-carboxyethyl)triphenylphosphonium bromide [21] provided am ixture of the E-and Z-alkenes 9 and 10.Aswe could not separate these dienes by flash chromatography (using silica gel or AgNO 3impregnated silica gel), they were purified by RP-HPLC and assigned the geometry of the D (2,3) and D (7,8) olefin functions in each isomer following analysis of NOESY spectra, as indicated in Figure 3.…”