Organocatalytic asymmetric synthesis of 5-(trialkylsilyl)cyclohex-2-enones and the transformation into useful building blocks.
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 TMS-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-1alpha,25-dihydroxyvitamin D3 are also presented.
Bolze
Patrick
P
Danish National Research Foundation Center for Catalysis, Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.
Dickmeiss
Gustav
G
Jørgensen
Karl Anker
KA
D000447:Aldehydes / Q000737:chemistry; D002384:Catalysis; D003512:Cyclohexanones / Q000138:chemical synthesis*; D053138:Cyclohexenes / Q000138:chemical synthesis; D004952:Esters / Q000737:chemistry; D007659:Ketones / Q000737:chemistry; D011759:Pyrrolidines / Q000737:chemistry; D013237:Stereoisomerism; D014297:Trimethylsilyl Compounds / Q000737:chemistry
D000447:Aldehydes; D003512:Cyclohexanones; D053138:Cyclohexenes; D004952:Esters; D007659:Ketones; D011759:Pyrrolidines; D014297:Trimethylsilyl Compounds; C010509:prolinol