Download PDF
Synlett 2002(5): 0787-0789
DOI: 10.1055/s-2002-25334
LETTER
© Georg Thieme Verlag Stuttgart · New York

Oxidative [3+2] Cycloaddition Reactions of 1,3-Dicarbonyl Compounds to Exocyclic Alkenes: The Regiospecific Synthesis of Spirodihydrofurans

Sengodagounder Muthusamy*, Chidambaram Gunanathan, Srinivasarao Arulananda Babu
Silicates and Catalysis Discipline, Central Salt and Marine Chemicals Research Institute, Bhavnagar 364 002, India
Fax: +91(278)567562, +91(278)566970; e-Mail: salt@csir.res.in;
Further Information

Publication History

Received 5 February 2002
Publication Date:
07 February 2007 (online)

   Permissions and Reprints All articles of this category

Abstract

Regiospecific synthesis of a variety of spirodihydrofurans was achieved using cerium(IV) ammonium nitrate mediated oxidative [3+2] cycloaddition of 1,3-dicarbonyl compounds to exocyclic olefins.

Key words

alkenes - cerium(IV) ammonium nitrate - 1,3-dicarbonyl compounds - oxidative cycloaddition - spirodihydrofuran

15

General procedure for the synthesis of spirodihydrofurans: A solution of CAN (2.2 mmol) in methanol (10 mL) was added to a methanolic solution (10 mL) containing exocyclic olefin (1 mmol) and 1,3-dicarbon-yl compound (1.2 mmol) at 0 °C with stirring under an argon atmosphere. The reaction proceeds rapidly and the reddish brown color of CAN disappears by the time the addition was over. After decolorization, the reaction mixture was diluted with water (50 mL) and extracted using dichloromethane
(3 × 30 mL). The combined organic extracts were washed with water and brine, dried over anhydrous magnesium sulfate and concentrated. The residue was purified through silica gel column chromatography (10% ethyl acetate-hexane) to furnish spirodihydrofurans (8a-p).

16

All new compounds gave satisfactory spectroscopic data consistent with their structures. Selected spectral data, 8a: Yellow solid, mp 69-70 °C; IR (CHCl3): = 2909, 1667, 1598, 1452, 1390, 1245, 1154, 1102, 1064, 983, 937, 918, 733 cm-1; 1H NMR (200 MHz, CDCl3): δ = 1.57-1.62 (m, 2 H), 1.74-1.83 (m, 10 H), 2.15-2.23 (m, 8 H), 2.78 (s, 2 H); 13C NMR (50.3 MHz, CDCl3): δ = 16.1 (CH3), 26.1 (CH), 29.8 (CH3), 33.6 (CH2), 35.1 (CH2), 37.7 (CH), 38.0 (CH2), 41.0 (CH2), 92.9 (quat-C, C-5), 112.5 (quat-C, C-3), 169.2 (quat-C, C-2), 195.1 (quat-C, C=O); MS: m/z = 246 (M+); Anal. Calcd for C16H22O2: C, 78.01; H, 9.00. Found: C, 78.05; H, 8.98. 8m: Yellow solid; mp 83-84 °C; IR (CHCl3): = 2928, 1679, 1603, 1467, 1378, 1258, 1144, 1073, 937, 631 cm-1; 1H NMR (200 MHz, CDCl3): δ = 0.89 (s, 3 H, CH3), 0.97 (s, 3 H, CH3), 1.01 (s, 3 H, CH3), 1.09-1.63 (m, 9 H), 1.65-1.80 (m, 3 H), 2.18-2.23 (m, 8 H), 2.88 (d, 1 H, J = 6.0 Hz); 13C NMR (50.3 MHz, CDCl3, mixture of diastereomer, * denotes minor isomer): δ = 15.4* (CH3), 15.6 (CH3), 21.3* (CH2), 22.1 (CH2), 24.0* (CH2), 24.6 (CH2), 24.8 (CH2), 24.9* (CH2), 25.5 (CH3), 28.5* (CH2), 29.6 (CH3), 29.7 (CH3), 30.8* (CH3), 31.4* (CH3), 32.9* (CH2), 33.4 (quat-C), 33.5 (quat-C), 34.1 (CH3), 35.5* (CH2), 37.6* (CH2), 38.5 (CH2), 38.8 (CH2), 39.3* (CH2), 41.0* (CH2), 45.7 (CH), 48.0 (quat-C), 49.5 (CH), 51.4* (CH), 63.5 (CH), 113.1 (quat-C), 166.5 (quat-C), 194.7 (quat-C, C=O). MS: m/z = 303 (M + 1, 43.5), 302 (M+, 76.5), 287 (22.6), 260(100), 241 (35.7), 217 (28.7), 190 (40.9), 189(72), 164(44), 150 (61.7), 119 (69.6), 105(79), 91 (74.8), 67 (74.8); Anal. Calcd for C20H30O2: C, 79.42; H, 10.00. Found: C, 79.48; H, 9.97.