Novel Syntheses of α,β-Unsaturated Esters, α,β-Unsaturated γ-Lactones, and 2-Alkoxypyrroles via 1,2,4-Triazole-Stabilized Allenic Anions

Abstract

The dianion 12 (right harpoon over left harpoon 13) of 1-(1,2,4-triazol-1-yl)phenylpropargyl ethyl ether 11(readily prepared from phenylpropargylaldehyde diethyl acetal 8 and 1,2,4-triazole) reacts with alkyl halides, aldehydes, ketones, and alpha,beta-unsaturated ketones to give exclusively gamma-substituted allenic products of type 10. These adducts underwent mild in situ hydrolysis enabling convenient syntheses of alpha,beta-unsaturated esters 9a-c and alpha,beta-unsaturated gamma-lactones 16, 18, 20, and 22. Reactions of dianion 13 with imines generated the 1,3,4-trisubstituted 2-alkoxypyrroles 27, 30, and 31 in high yields. The alkyl-substituted analog 34 underwent similar reactions to give predominantly the gamma-products 39,40, and 42 along with a small proportion of alpha-analogs.

A facile approach to spirocyclic butenolides through cascade cyclization/oxidative cleavage reactions of (Z)-enynols catalyzed by gold under dioxygen atmosphere

“…91, 14.49, 19.55, 29.46, 33.78, 88.50, 126.57, 126.68, 126.97, 128.73, 129.54, 131.70, 138.53, 175.60, 179 d 13.81, 22.14, 22.20, 30.43, 30.91, 30.96, 33.43, 33.69, 86.46, 117.96, 123.87, 127.94, 128.66, 128.76, 132.31, 138.82, 163.86, 171.30 12, 24.50, 34.42, 89.43, 115.64, 127.52, 128.88, 130.30, 130.92, 171.82, 172.76. The spectral data is in agreement with reported data [14]. dec-3-en-2-one (7j)…”

Palladium-Catalyzed Hydrophenylation of Alkynes with Sodium Tetraphenylborate under Mild Conditions

“…TLC was performed with silica gel (0.045-0.075 mm). 1 H NMR (300 MHz) chemical shifts (δ) were referenced to TMS and 13 C NMR (75 MHz) chemical shifts (δ) were referenced to internal solvent resonance. GC analyses of organic compounds were performed on a GC instrument with a capillary 25m column.…”

“…2h was obtained in 245.9 mg (0.96 mmol, 96 %) as pale yellow oil. 2-Phenyloct-1-ene 2a [1] (93% purity, with 7% of (E)-1-phenyloct-1-ene): yellow oil; 1 H NMR (300 MHz, CDCl 3 ) δ 7.39-7.21 (m, 5H), 5.24 (d, 1H, J = 1.5 Hz), 5.03 (d, 1H, J = 1.5 Hz), 2.48 (t, 2H, J = 7.4 Hz), 1.48-1.23 (m, 8H), 0.86 (t, 3H, J = 6.9 Hz); 13 2-Phenylhept-1-ene 2b [2] (91% purity, with 9% of (E)-1-phenylhept-1-ene): yellow oil; 1,1-diphenylethene 2c [3] : red brown oil; 1 2d Cl 5-Chloro-2-phenylpent-1-ene 2d [4] (90% purity, with 10% of (E)-5-chloro-1-phenylpent-1-ene): yellow oil; 1 H NMR (300 MHz, CDCl 3 ) δ 7.41-7.30 (m, 5H), (E)-3-Phenylhex-3-ene 2e [6] : pale yellow oil; 1 H NMR (300 MHz, CDCl 3 ) δ 7.36-7.17…”

“…(m, 5H), 5.63 (t, 1H, J = 7.2 Hz), 2.50 (q, 2H, J = 7.4 Hz), 2.20 (quint, 2H, J = 7.6 Hz), 1.05 (t, 3H, J = 7.4 Hz), 0.98 (t, 3H, J = 7.6 Hz); 13 (E)-4-Phenyloct-4-ene 2f [6] : pale yellow oil; 1 (E)-5-Phenyldec-5-ene 2g [5] : pale yellow oil; 1 Triphenylethene 2h [3] : pale yellow oil; 1 Dimethyl 2-phenylmaleate 2i [7] : yellow oil; 1 (E)-1,2-Diphenylpropene 2j [6] : white solid, mp o C; 1 H NMR (300 MHz, CDCl 3 ) δ 1,1-Diphenylpropene 3j [6] : colorless oil; 1 (E)-Methyl 3-phenylbut-2-enoate 2k [8] : pale yellow oil; 1 (E)-3-methyl-1-phenyl-buta-1, 3-diene 4 [9] : pale yellow oil; 1 H NMR (300 MHz, (E)-2,4-diphenylbut-3-en-2-ol 3m [10] : yellow oil; 1 (1Z,3Z)-1,4-Diphenyl-1,4-bis(trimethylsilyl)buta-1,3-diene 7 [11] : yellow oil; 1 (1Z,3Z)-1,2,3,4-Tetraphenylbuta-1,3-diene 8 [12] : yellow solid, mp 135- (E)-Ethyl 3-phenyloct-2-enoate 2n [13] : pale yellow oil; 1 Methyl 3,3-diphenylacrylate 2o [14] : pale yellow oil; 1 (E)-1,2-diphenylhex-1-ene 2p [15] : colorless oil; 1 1,1-diphenylhex-1-ene 3p [16] : colorless oil; 1 2-Phenyloct-1-ene 2a-d [1] : yellow oil; 1 Triphenyl boroxin in equilibrium with Phenylboronic acid [17] : white solid, mp…”

Acyl anion synthons: benzotriazole stabilized compared to classical

“…129 Treatment of dianion 217 with imines at -78 °C for several minutes produced adduct 228, which on quenching with water at the same temperature and subsequent hydrolysis gave product 229 (Scheme 38). In contrast, prolonged keeping of 228 at -78 °C resulted in cyclization by intramolecular substitution of triazole giving pyrrole 230.…”