Alpha,alpha'-annulation of 2,6-prenyl-substituted cyclohexanone derivatives with malonyl chloride: application to a short synthesis of (+/-)-clusianone. Formation and rearrangement of a biogenetic-like intermediate.
Conditions were found for the successful Effenberger alpha,alpha'-annulation of 3,3-dimethyl-2,4,6-triprenyl cyclohexanone silyl enol ethers with malonyl chloride to give the corresponding bicyclo[3.3.1]nonane-trione in 35% yield, this result allowing a short synthesis of (+/-)-clusianone. An isomeric rearranged bicyclo[3.3.1]nonane-trione was also isolated in 25% yield, and changing the Lewis acid resulted in formation of a lavandulyl-substituted phloroglucinol derivative in 38% yield. The mechanism of formation of these two last products mimics the biogenetic pathway to PPAPs. [reaction: see text].
Nuhant
Philippe
P
Institut de Chimie des Substances Naturelles, CNRS, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
David
Marc
M
Pouplin
Thomas
T
Delpech
Bernard
B
Marazano
Christian
C
D001577:Benzophenones; D016227:Benzoquinones; D040761:Biomimetic Materials / Q000138:chemical synthesis* / Q000737:chemistry; D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D003512:Cyclohexanones / Q000138:chemical synthesis* / Q000737:chemistry; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
C118110:7-epiclusianone; D001577:Benzophenones; D016227:Benzoquinones; D001643:Bridged Bicyclo Compounds; D003512:Cyclohexanones; D006843:Hydrocarbons, Chlorinated; C036468:cyclohexanone