Friedel Crafts acylation, photochemical

The 977-pyrido[3,4- ]pyrrolizin-9-one 145 has been prepared for its photochemical properties. The preparation involves an intramolecular Friedel-Crafts acylation of the acid chloride formed from 3-(l-pyrrolyl)pyridine-4-carboxy-late (Scheme 40). The product is a photosensitizer, which absorbs visible light its absorption spectra are pH, solvent, and concentration dependent <1994SAA57>. 

These diketones with different aryl groups at the ends were needed for a photochemical experiment. The compounds could be prepared by successive Friedel-Crafts acylations with a diacid dichloride but the yields were poor. Why is this a bad method Suggest a better synthesis. 

Case Study 6.25 Green photochemistry - photochemical Friedel-Crafts acylation... 

Oelgemoller, M., Mattay, J., The Photochemical Friedel Crafts Acylation of Quinones from the Beginnings of Organic Photochemistry to Modem Solar Chemical Applications. In Horspool, W. M., Lenci, F. (eds), CRC Handbook of Organic Photochemistry and Photobiology, 2nd edn, CRC Press LLC, Boca Raton, FL, 2004, Chapter 88, pp. 1 16. 

Friedel-Crafts acylation of furan gives 2-acylfurans. A complementary photochemical procedure has been published for the preparation of 3-acylfurans which involves irradiation of a furan in the presence of a thioamide. The reaction is proposed to occur by regioselective Paterno-BUchi addition of the thioamide to the furan the thietane produced then eliminates and hydrolyses to the observed product. 

Friedel-Crafts acylation catalyst, 95, 96 MA polymerization catalyst, 254 Stannous chloride, 460 Stannous oxalate, 480 Starch, MA condensations, 516 Steroids, MA Diels-Alder synthesis, 145 Steryl methacrylate, MA copolymerization, 528 Stilbene, cis and trans, 202 MA copolymerization, 307, 373, 374, 379, 394 MA reactivity ratios, 302 Stilbene oxide, MA photochemical addition, 197, 228... 

The "Photochemical Friedel-Crafts Acylation" of Quinones From the Beginnings of... 

From 1992, Kraus and co-workers explored the synthetic value of the photochemical acylation of 1,4-quinones (Scheme 32 Table 88.11), and developed it as a suitable alternative to existing thermal Friedel-Crafts acylations.During their studies on the pyranoquinone skeleton, they initially used the classical Friedel-Crafts approach but the poor solubUity of some of the starting materials, the drastic reaction... 

The parent TMM complex (190 R = H) undergoes photochemical ligand substitution with trifluorophosphine or trimethylamine Al-oxide assisted substitution with tertiary phosphines or t-butyl isocyanide (Scheme 5A) Trimethylamine A-oxide assisted substitution using isoprene as the incoming ligand results in C-C bond formation to afford the bis-TT-allyl complex (197). An intramolecular version of this reaction is also known.The parent complex (190 R = H) reacts with electrophiles. Addition of HCl or Br2 gives the methallyl complexes (192) and (198), respectively. Tetrafluoroethylene adds across the Fe bond to afford (199) under photochemical conditions. Complex (190) undergoes Friedel-Crafts-type acylation with... 

Decarbonylation of (14), either thermally in boiling hexane (X = Cl, Br) or photochemically (X = 1), gives the halide-bridged dimers [ReX(CO)4]2 (15) that catalyze Friedel-Crafts alkylation and acylation, as well as benzyl ester deprotection. 

Ferrocene, Fe(Ti5-C5H5)2, and related cyclopentadienyl complexes of transition metals in fact are far more thermally stable, less reactive substances than ionic cyclopentadienides, and have an extensive derivative chemistry that is typically aromatic in that their C-H bonds can undergo such electrophilic substitution reactions as Friedel-Crafts alkylation or acylation, nitration, and so on. Moreover, as a substituent, the ferrocenyl group (ri -f sl l5)Fc(ri -( 5l I4) (=R) is even more effective than a phenyl substituent in stabilizing carbenium ions [RCH2]+. The redox and photochemical properties of many metaUocenyl residues make them versatile substituents with many chemical and materials applications. ... 

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