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Synlett 2007(19): 3068-3072  
DOI: 10.1055/s-2007-992364
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthesis and Reactions of meso-Triphenylporphyrin Grignard Reagent

Dong-Mei Shen, Chao Liu, Qing-Yun Chen*
Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, 200032 Shanghai, P. R. of China
Fax: +86(21)64166128; e-Mail: chenqy@mail.sioc.ac.cn;
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Publication History

Received 5 September 2007
Publication Date:
08 November 2007 (online)

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Abstract

(5-Bromo-10,15,20-triphenylporphyrinato)nickel(II) reacts with Rieke magnesium in DME to produce the correspondding porphyrin Grignard reagent. Its subsequent reactions with aldehydes and ketones resulted in the formation of desired meso-alcohol-substituted porphyrins Ni7 and unexpected meso-ketone-substituted porphyrins Ni4, respectively.

Key words

bromoporphyrins - highly active magnesium - Grignard reagent

7

Typical Procedure for the Grignard Reactions of Bromoporphyrin Ni3 with Ketones or Aldehydes
Freshly cut potassium (65 mg, 20 equiv), MgCl2 (190 mg, 20 equiv), KI (275 mg, 20 equiv), and DME (10 mL) were placed in an oven-dried 50 mL Schlenk flask under N2. The mixture was stirred and heated to reflux for 2 h and cooled to r.t. A DME (20 mL) solution of Ni3 (50 mg, 1.0 equiv)and cyclohexanone (2a, 175 mL, 20 equiv) was then charged with a syringe slowly under N2. After 5 min, the mixture was diluted with CH2Cl2 (30 mL), quenched with sat. NH4Cl solution, and washed with H2O three times. The organic layer was passed through dry silica gel and evaporated to dryness. The resulting solid was purified by flash column chromatography (silica gel, 300-400 mesh, PE-CH2Cl2, 1:1 v/v) to afford Ni4a (33 mg, 65% yield).
Spectroscopy data of Ni4a are as follows: 1H NMR (300 MHz, CDCl3): δ =2.13-2.46 (m, 4 H), 2.79-3.10 (m, 4 H), 5.48-5.54 (m, 1 H), 7.67 (d, J = 5.7 Hz, 9 H), 7.96 (d, J = 6.3 Hz, 6 H), 8.67 (s, 4 H), 8.74 (d, J = 5.1 Hz, 2 H), 8.96 (d, J = 5.1 Hz, 2 H). MS (MALDI): m/z = 690.2 [M+]. UV/Vis (CH2Cl2): λmax (relative intensity) = 416 (14.8), 533 (1.0) nm. Anal. Calcd for C44H32N4NiO×1.5H2O: C, 73.56; H, 4.91; N, 7.80. Found: C, 73.47; H, 4.76; N, 7.52. IR (KBr): 2930, 1710, 1598, 1440, 1349, 1124, 1007, 792, 747, 701 cm-1.
Spectroscopy data of Ni7a are as follows: 1H NMR (300 MHz, CDCl3): δ =3.36 (s, 1 H), 7.26 (3 H, overlapping with the signal of CDCl3), 7.54 (d, J = 6.6 Hz, 2 H), 7.67 (br s, 9 H), 7.97 (br s, 6 H), 8.70 (br s, 6 H), 9.29 (br s, 2 H). MS (MALDI): m/z = 700.2 [M+]. UV/Vis (CH2Cl2) λmax (relative intensity) = 415 (14.7), 529 (1.0) nm. HRMS (MALDI): m/z calcd for C45H30N4NiO+ [M+]: 700.1798; found: 700.1768.