Total synthesis of (+)-cassaine utilizing an anionic polycyclization strategy
Kontham Ravindar1, Pierre-Yves Caron, Pierre Deslongchamps
1Département de Chimie, Faculté des Sciences et de Génie, Pavillon Alexandre-Vachon, Université Laval , 1045, avenue de la Médecine, Québec City, QC G1V 0A6, Canada , and Département de Chimie, Université de Sherbrooke , Sherbrooke, QC, J1K 2R1 Canada.
Abstract:
A stereoselective total synthesis of (+)-cassaine (1) via an anionic polycyclization methodology is described. Commercially available (+)-carvone (5), the only chiral source, was used to fix the entire stereochemistry of the natural product. Anionic polycyclization of a new substituted 2-(methoxycarbonyl)cyclohex-2-en-1-one (4) with known 1-phenylysulfinyl-3-penten-2-one (3) provided the versatile tricycle (2) with requisite stereochemistry. A sequence of functional group manipulations of tricycle (2) furnished the natural product 1.
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