Réaction #822469

Équation de réaction

trans-2-cyclopentadecen-1-one

cyclopentadiene

perchloric acid

(2S, 5S)-5-benzyl-3-methyl-2-(5-methyl-furan-2-yl)-imidazolidin-4-one

→

title compound

Rendement 88.0%

(1R, 2R, 16S, 17R)-Tricyclo[15.2.1.0˜2,16˜]eicos-18-en-3-one

Rendement 88.0%

Solvants

water

Conditions de réaction

Traitement

1. 1
   AutrePrepared
2. 2
   AutrePurification by flash chromatography (9:1 ethyl acetate:hexanes)

Mode opératoire

Prepared according to general procedure A from trans-2-cyclopentadecen-1-one (100 mg, 0.45 mmol), cyclopentadiene (56 μL, 0.67 mmol), 70% aqueous perchloric acid (7.8 μL, 0.09 mmol) and (2S, 5S)-5-benzyl-3-methyl-2-(5-methyl-furan-2-yl)-imidazolidin-4-one (24.3 mg, 0.09 mmol) in water (150 μL) for 72 hours at 0° C. Purification by flash chromatography (9:1 ethyl acetate:hexanes) provided the title compound as a clear, colorless crystalline solid in 88% yield (114 mg, 0.50 mmol); 5:1 endo:exo, endo 93% ee. IR (film) 3052, 2922, 2854, 1698, 1456, 1368, 1331, 1225, 1126, 1084, 1016, 905.5, 884.9, 714.4 cm−1; 1H NMR (300 MHz, CDCl3) δ 6.21 (dd, J=5.4, 2.7 Hz, 1H, CH═CH), 5.86 (dd, J=5.4, 2.7 Hz, 1H, CH═CH), 3.09 (m, 1H, CHCH═CH), 2.61 (m, 2H, CHCO and one of CH2CO), 2.52 (m, 1H, CHCH═CH), 2.41 (m, 1H, one of CH2CO), 2.27 (m, 1H, CHCHCO), 1.81-1.24 (br m, 22H, (CH2)11); 13C NMR (75 MHz, CDCl3) δ 211.6, 138.5, 132.6, 59.6, 48.4, 47.2, 46.7, 41.5, 41.3, 36.3, 28.0, 27.9, 27.7, 27.2, 26.8, 26.8, 26, 26.7 26.0, 23.6. [α]D=+22.2 (c=1.0, CHCl3). Product ratios were determined by GLC analysis (200° C., 23 psi); (1R, 2R, 16S, 17S) endo isomer tr=20.1 min, and (1S, 2S, 16R, 17R) endo isomer tr=19.6 min, exo isomers tr=19.0, 18.6 min. The trans relative stereochemistry of C-16 and C-17 was confirmed by the presence of an NOE between the C-16 methine proton and the two C-19 protons.

Source