5061-81-4Relevant articles and documents
Photochemical preparation of highly functionalized 1-indanones
Wessig, Pablo,Glombitza, Clemens,Mueller, Gunnar,Teubner, Janek
, p. 7582 - 7591 (2007/10/03)
A series of o-alkylphenyl alkyl ketones 1 were synthesized by different methods. The presence of a leaving group X adjacent to the carbonyl group is the special peculiarity of these ketones. Upon irradiation the keto carbonyl group of these compounds undergoes an n-π* excitation followed by a 1,5-hydrogen migration from the o-alkyl substituent to the carbonyl oxygen atom. The thus formed 1,4-diradicals are subject to a very rapid elimination of acid HX, giving 1,5-diradicals. We called this process spin center shift. After intersystem crossing these diradicals cyclize to 1-indanones 20 in good yields. Depending on the solvent and on substituents, o-alkoxyalkyl ketones 22 or benzo-[c]furanes 21 are obtained as byproducts. The mechanism of the cyclization was elucidated by quantum chemical calculations and kinetic measurements.
Enantioselective synthesis of (S)-2-hydroxypropanone derivatives by benzoylformate decarboxylase catalyzed C-C bond formation
Duennwald, Thomas,Demir, Ayhan S.,Siegert, Petra,Pohl, Martina,Mueller, Michael
, p. 2161 - 2170 (2007/10/03)
Chiral 2-hydroxypropanone derivatives 5a-v, 8a-d, and 10a, b were formed by benzoylformate decarboxylase (BFD) catalyzed C-C bond formation. A donor aldehyde and acetaldehyde as an acceptor were carboligated in aqueous buffer solution with remarkable ease in high chemical yield and good to high optical purity. The substrate range of this thiamin diphosphate dependent enzyme was examined to employ this benzoin condensation type reaction in stereoselective synthesis. The observed dependence of the enantiomeric excess on the substitution pattern could be exploited to design substrates resulting in high selectivity. Best substrates with regard to optical purity were meta- substituted benzaldehyde derivatives. To enable a general and convenient applicability of the BFD-catalyzed C-C bond formation, analytical batch experiments were scaled up to give (S)-2-hydroxy ketones in good to high yields on a preparative scale. Further, the solubility of some of the organic substrates in aqueous solution was increased by the use of cyclodextrin or buffer/DMSO mixtures.
