Acid-Catalyzed Synthesis of Methylene-Bridged (<i>S</i>)-Tyrosine−Phenol Dimers

Bew, Sean P.; Hughes, David L.; Sharma, Sunil V.

doi:10.1021/jo0610863

Cited by 10 publications

(1 citation statement)

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“…However, we realized that intermediate 5 can also be considered as a Mannich derivative of o -phenol, which often served as a good precursor to generate o -quinone methides . Investigation showed that this generation could be influenced by thermal initiation, photoirradiation, or bases (Scheme ). Deductively, when 5 is treated by one of those conditions, the corresponding o -quinone methide may be formed accompanied by an N -debenzylation.…”

Section: Resultsmentioning

confidence: 99%

Preparation of Enantiopure Substituted Piperidines Containing 2-Alkene or 2-Alkyne Chains: Application to Total Syntheses of Natural Quinolizidine-Alkaloids

Cheng

Wang

et al. 2010

J. Org. Chem.

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S3 Experimental Section General Experimental Methods: IR spectra were recorded as KBr pellets. The 1 H NMR (300 MHz) and 13 C NMR (75 MHz) spectra were recorded in D 2 O or CDCl 3. The J values are given in Hz. MS (EI) spectra were obtained at 70 eV. PE is petroleum ether (60-90 o). N O 8a A Typical Procedure for Preparation of (7aS,11S,13R)-11-Isopropenyl-13phenyl-7a,8,10,11-tetrahydro-9H,13H-naphtho[1,2-e]pyrido[2,1-b][1,3]oxazine (8a): To a cold solution (ice-water bath) of 6 (4.32 g, 10 mmol) in dry THF (70 mL) was added isopropenylmagnesium bromide (0.5 M in THF, 6 mL, 30 mmol) dropwise under nitrogen. After the reaction was stirred at 0 °C for 1.0 h (monitored by TLC), a saturated aqueous solution of NH 4 Cl (30 mL) was added to quench the reaction. Then the resultant mixture was extracted with CH 2 Cl 2 (3 x 30 mL). The combined organic layers were washed with H 2 O and brine and dried over anhydrous Na 2 SO 4. After removal of the solvent, the residue was purified by chromatography (silica gel, EtOAc:PE ＝ 1:15) to give the desired product 8a (3.26 g, 92%) as a colorless crystal, mp 130-131 o C, [α] D

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Section: Resultsmentioning

confidence: 99%