Aryl alkene ketone

The benzylic position of an alkylbcnzene can be brominated by reaction with jV-bromosuccinimide, and the entire side chain can be degraded to a carboxyl group by oxidation with aqueous KMnCfy Although aromatic rings are less reactive than isolated alkene double bonds, they can be reduced to cyclohexanes by hydrogenation over a platinum or rhodium catalyst. In addition, aryl alkyl ketones are reduced to alkylbenzenes by hydrogenation over a platinum catalyst. 

Oxathiolanes and 1,3-dioxolanes containing a 2-phenyl substituent react with alkyl-lithium reagents to produce aryl alkyl ketones and alkenes (65JOC226). The mechanism of this reaction is discussed in Section 4.30.2.2.7. 

Chalcones can be prepared by a Heck reaction between an aryl iodide and an aryl vinyl ketone. Demethylation allows spontaneous cyclisation to the flavanone <03TL9107>. An arene-alkene photocyclisation is observed during the irradiation of dihydro-2-methyl-2-vinylnaphtho[l,2-6]pyran-4-one and benzotricyclo[5.3.1.0 ]undecenes 24 result <03TL2011>. 

Sano, S., Takehisa, T., Ogawa, S., Yokoyama, K., Nagao, Y. Stereoselective synthesis of tetrasubstituted (Z)-alkenes from aryl alkyl ketones utilizing the Horner-Wadsworth-Emmons reaction. Chem. Pharm. Bull. 2002, 50, 1300-1302. 

This reaction has very general application in the formation of C-C bonds, including biaryls, aryl alkenes, alkanes, and even ketones. ... 

Arylthallium bis(trifluoroacetate)s are converted by successive treatment with KF and BF3 into aryl fluorides.Thallium(iii) nitrate (TTN) readily oxidizes dialkyl sulphides and selenides to the corresponding sulphoxides or selenoxides, and 2-(alkylthio)-l-arylethanones (37) into compounds (38) in methanolic solution.In a modification of the TTN oxidative conversion of aryl alkyl ketones into arylacetic acids, enol ethers derived from the ketones are used instead of the ketones themselves. This reduces the formation of side products. Cyclic aralkyl ketones (39) may be ring-expanded and alkylated to give compounds (40) via treatment of their Wittig-derived alkenes with TTN/ an extrapolation of the basic reaction discovered previously. 

Table 3.1 Representative Asymmetric Epoxidation of Aryl Alkenes with Chiral Ketones.

Like ketone 44a, these N-aryl-substituted ketones have also been found to be highly effective for a variety of alkenes, including cis-P-methylstyrenes [24f], chromenes... 

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