A new method for the meta acylation of anisole and its para-methyl or fluoro derivatives, is described. Addition of two trimethysilyl groups in the 2 and 5 positions (relative to the methoxy group), followed by hydrolysis affords the corresponding 5-trimethylsilyl-3-Cyclohexenones. Electrophilicsubstitution of the silyl group using RCOCl/2AlCl3 at low temperature provides, after final aromatisation
Simple and Practical Routes to Enantiomerically Pure 5-(Trialkylsilyl)-2-cyclohexenones
作者:Georgios Sarakinos、E. J. Corey
DOI:10.1021/ol990805f
日期:1999.9.1
[reaction: see text] Enantiomerically pure chiral 5-silylated 2-cyclohexenones are easily prepared in high yield using as a key step kinetic resolution with a commercially available lipase. Fully active enzyme can be recovered very efficiently for reuse. The synthetic steps are outlined in Schemes 1 and 3. Enantiomerically pure 2-cyclohexenones such as 1 and 2 are versatile intermediates for the synthesis
Synthesis of 3-Benzoylcyclohexanone, A key Intermediate for the Synthesis of Ketoprofen
作者:Bernard Bennetau、Michele Krempp、J. Dunoguès
DOI:10.1080/00397919408012628
日期:1994.1
Abstract A simple and convenient synthesis of 3-benzoylcyclohexanone, a ketoprofen precursor, is proposed. It consists of the preparation of 5-trimethylsilyl-3-cyclohexenone via disilylation of anisole followed by hydrolysis and subsequent regiospecific benzoylation and hydrogenation.
A simple organocatalytic approach to highly attractive chiral building blocks is presented. By the reaction of beta-ketoesters with alpha,beta-unsaturated aldehydes using a chiral TINS-protected prolinol as the catalyst, optically active 5-(trialkylsilyl)cyclohex-2-enones are formed in good yields and with 98-99% ee. The applications of 5-(trialkylsilyl)cyclohex-2-enones for the formation of 5-(hydroxy)cyclohex-2-enones and the A-ring of 19-nor-1 alpha,25-dihydroxyvitamin D-3 are also presented.
(R)- and (S)-5-trimethylsilyl-2-cyclohexenone: a versatile chiral source for the synthesis of optically active cyclohexanone derivatives