Synlett 2006(12): 1943-1947  
DOI: 10.1055/s-2006-947337
LETTER
© Georg Thieme Verlag Stuttgart · New York

Reactions of Arylvinylidenecyclopropanes with Bromine and Iodine

Min Shi*a, Ming Maa, Zhi-Bin Zhua, Li Weib
a School of Chemistry & Pharmaceutics, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, P. R. of China
Fax: +86(21)64166128; e-Mail: Mshi@pub.sioc.ac.cn;
b State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, P. R. of China
Further Information

Publication History

Received 25 April 2006
Publication Date:
24 July 2006 (online)

Abstract

Reactions of arylvinylidenecyclopropanes 1 with equimolar amount of bromine or iodine at low temperature produced the corresponding addition products 2, 3 and 5, 6 in moderate to good yields at -40 °C and -100 °C, respectively. On the other hand, the reactions of 1 with equimolar amount of iodine gave the corresponding iodinated naphthalene derivatives 4 via the ­corresponding addition products 3 under similar conditions at 25 °C. The further transformation of the addition product 6a has been presented.

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The crystal data of 2c has been deposited in CCDC with number 273885. Empirical formula: C24H20Br2; formula weight: 468.22; crystal color, habit: colorless, prismatic; crystal dimensions: 0.506 × 0.367 × 0.331 mm; crystal system: triclinic; lattice type: primitive; lattice parameters: a = 8.721 (3)Å, b = 11.157 (3)Å, c = 11.857 (3)Å, α = 109.253 (5)°, β = 106.367 (5)°, γ = 95.731 (5)°, V = 1021.1 (5)Å3; space group: P-1; Z = 2; D calcd = 1.523 g/cm3; F 000 = 468; diffractometer: Rigaku AFC7R; residuals: R1 = 0.0739, wR2 = 0.1669. A colorless solid, mp 175.1-176.3 °C. IR (CH2Cl2): 3052, 3018, 2960, 2920, 2851, 1613, 1591, 1513, 1488, 1442, 1381, 1261, 1030, 813, 699, 745 cm-1. 1H NMR (300 MHz, CDCl3, TMS): δ = 1.22 (1 H, dd, J 1 = 8.1 Hz, J 2 = 8.1 Hz, CH), 1.70 (1 H, dd, J 1 = 8.7 Hz, J 2 = 8.7 Hz, CH), 2.40 (3 H, s, Me), 2.90 (1 H, dd, J 1 = 8.1 Hz, J 2 = 8.1 Hz, CH), 6.94-7.08 (4 H, m, Ar), 7.16-7.26 (5 H, m, Ar), 7.33-7.43 (5 H, m, Ar). MS (EI): m/z (%) = 468 (1.75) [M+], 389 (13.50), 388 (21.71), 387 (14.75), 309 (15.26), 308 (67.40), 307 (100), 293 (26.93), 292 (32.96), 229 (55.53), 215 (85.84), 189 (18.23), 105 (13.53). HRMS (EI): m/z calcd for C24H20Br2 [M+]: 465.9916; found: 465.9932.

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The spectroscopic data (1H NMR and 13C NMR spectral data) and analytic data of the compounds shown in Tables [1 ] - [4] , Scheme [1] and the detailed description of experimental procedures are available free of charge via the Internet.

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General Reaction Procedure.
A solution of iodine (88 mg, 0.3 mmol) in DCE (5.0 mL) was added dropwise into a solution of diphenylvinylidene-cyclopropane (1a, 76 mg, 0.3 mmol) in DCE (2.0 mL). The reaction mixture was stirred for 6 h at -40 °C (monitored by TLC). After the starting materials 1a were consumed. The solvent in filtration was removed under reduced pressure and the residue was subjected to a flash column chromatography to give the desired product 3a (133 mg, 81%) as a yellow solid.