Total synthesis of cembranolides

Chemical correlation of pseudoplexaurol (182) with 183, 184 and attempted conversion to 14-deoxycrassin (239). 

In 1987, Marshall and Crooks reported the addition of lithium dimethylcuprate to the conjugated cycloalkynone 276 to yield, after equilibration, a single -enone 277, which was converted via acidic hydrolysis, oxidation, and reduction to 

Reagents and conditions (a) Mn02, 92% (b) Mn02, NaCN, MeOH, HOAc, 58% (c) Z11CI2, CH2CI2, 0°C to 30°C, 71%. 

5 STUDIES ON NOVEL MACROCYCLIZATION METHODS OF CEMBRANE-TYPE DITERPENOIDS 

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Marshall, (.A. and Gung, W.Y (1988) Stereoselective total synthesis of cembranolides through cydization of a homochiral (a-alkoxyallyl) stannane precursor. Tetrahedron Lett., 29, 3899-3902. 

Nishitani, K., Konomi, T, Mimaki, Y, Tsimoda, T, and Yamakawa, K. (1993) Total synthesis of ( )-cembranolide via Cr(ll) mediated intramolecular macrocydization of p-alkoxycarbonylallyl halide. Heterocydes, 36,1957-1960. 

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