메뉴 건너뛰기
Synlett
Volumn , Issue 7, 2008, Pages 979-982
Novel synthesis of nine-membered oxa-heterocycles by Pd(0)-catalyzed intramolecular Heck reaction via unusual 9-endo-trig-mode cyclization
Author keywords

9 endo trig; Claisen rearrangement; Intramolecular Heck reaction; Medium sized ring compounds; Oxa heterocycles; Pd(OAc) 2 catalyst
Indexed keywords

HETEROCYCLIC COMPOUND; OXA HETEROCYCLE DERIVATIVE; PALLADIUM;
EID: 42949159912     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-2008-1072510     Document Type: Article
Times cited : (42)
References (51)
  • 1
    • 0003397781 scopus 로고    scopus 로고
    • Diederich, F, Stang, P. J, Eds, Wiley-VCH: New York
    • (a) Metal-Catalyzed Cross-Coupling Reactions; Diederich, F.; Stang, P. J., Eds.; Wiley-VCH: New York, 1998.
    • (1998) Metal-Catalyzed Cross-Coupling Reactions
  • 39
    • 42949095611 scopus 로고    scopus 로고
    • General Procedure for the Synthesis of Compounds 5a-f and 6a A mixture of the compound 4a (100 mg, 0.265 mmol, TBAB (1.2 equiv, dry KOAc (2.75 equiv) was taken in dry DMF, 10 mL) under nitrogen atmosphere. Then, the catalyst Pd(OAc)2 (10 mmol, 5.92 mg) was added and the mixture was stirred in an oil bath at 100 °C for about 2-3.5 h. The reaction mixture was cooled, and H2O (3 mL) was added. It was extracted with EtOAc (3 x 10 mL) and washed with H2O (2 x 10 mL, followed by brine, 15 mL, The organic layer was dried (Na2SO4) and evaporation of EtOAc furnished the crude mass, which was purified by column chromatography over silica gel. Elution of the column with 10% EtOAc-PE afforded the product 5a. Similarly, the other substrates 4b-f were subjected to the reaction under the same conditions to give products 5b-f and 6a
    • 4) and evaporation of EtOAc furnished the crude mass, which was purified by column chromatography over silica gel. Elution of the column with 10% EtOAc-PE afforded the product 5a. Similarly, the other substrates 4b-f were subjected to the reaction under the same conditions to give products 5b-f and 6a.
  • 49
    • 42949140515 scopus 로고    scopus 로고
    • Synthesis of the Precursors 4a-f; Typcial Procedure A mixture of compound 3 and different 2-bromobenzylbromides and dry K2CO 3 (2.0 mg) in dry acetone (75 mL) in the presence of NaI was refluxed for a period of 2-3 h. After cooling the reaction mixture was filtered and the solvent was removed. The residual mass was extracted with CHCl3, washed with H2O, followed by brine-H2O, and dried (Na 2SO4, Removal of CHCl3 gave a crude product, which was chromatographed over silica gel (60-120 mesh, Elution of the column with PE-EtOAc (2:1) gave compounds 4a-f. Compound 4a: yield 93, white solid, mp 101-102 °C. IR (KBr, νmax, 1649, 1701 cm-1. 1H NMR (400 MHz, CDCl3, δ, 1.24 (d, 3 H, CHCH3, J, 7.2 Hz, 3.32 (s, 3 H, NCH 3, 3.39 (s, 3 H, NCH3, 4.28-4.31 m, 1 H,=CHCH
    • 3: C, 53.84; H, 5.05; N, 7.39. Found: C, 53.88; H, 5.09; N, 7.23.
  • 50
    • 42949092000 scopus 로고    scopus 로고
    • Synthesis of Compounds 5a-f and 6a; General Procedure A mixture of the compound 4a (100 mg, 0.265 mmol, TBAB (1.2 equiv, dry KOAc (2.75 equiv) was taken in dry DMF (10 mL) under nitrogen atmosphere. Then, the catalyst Pd(OAc)2 (10 mmol, 5.92 mg) was added and the mixture was stirred in an oil bath at 100 °C for about 2-3.5 h. The reaction mixture was cooled, and H2O (3 mL) was added. It was extracted with EtOAc (3 x 10 mL, washed with H2O (2 x 10 ml, and followed by brine (15 mL, The organic layer was dried (Na2SO4, evaporation of EtOAc furnished the crude mass, which was purified by column chromatography over silica gel. Elution of the column with 10% EtOAc-PE afforded the product 5a. Similarly, the other substrates 4b-f were subjected to the reaction under the same conditions to give products 5b-f and 6a. Compound 5a: yield 90, white solid, mp 193-194 °C. IR KBr
    • 2O moiety. This was again confirmed by HMBC and COSY experiments.
  • 51
    • 42949102695 scopus 로고    scopus 로고
    • Compound 6a: yield 12, viscous liquid. IR (neat, νmax, 1648, 1701 cm-1. 1HNMR (400 MHz, CDCl3, δ, 2.34 (s, 3 H, CHCH3, 3.21 (s, 3 H, NCH3, 3.27 (s, 3 H, NCH3, 5.24 (s, 2 H, OCH 2, 6.02 (s, 1 H, CH, 7.19-7.25 (m, 2H, ArH, 7.26-7.33 (m, 2 H, ArH, MS: m/z, 284 [M, Anal. Calcd, ) for C 16H16N2O3: C, 67.59; H, 5.67; N, 9.85. Found: C, 67.71; H, 5.66; N, 9.88
    • 3: C, 67.59; H, 5.67; N, 9.85. Found: C, 67.71; H, 5.66; N, 9.88.

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.