ABSTRACT
The first enantioselective total synthesis of 10-isocyano-4-cadinene, a marine sesquiterpene isolated from nudibranchs of the family Phyllidiidae, and determination of its absolute stereochemistry were achieved. 10-Isocyano-4-cadinene is expected to be a novel nontoxic antifouling agent. In the synthesis, intermolecular Diels-Alder reaction and samarium diiodide induced Barbier-type cyclization were employed as key steps. The absolute configuration of 10-isocyano-4-cadinene was determined as (1S,6S,7R,10S) by comparison of the optical rotations between natural and synthetic samples. In addition, the authors successfully synthesized 10-epi- and di-1,6-epi-10-isocyano-4-cadinene through the same synthetic pathway. Antifouling activities against Balanus amphitrite with the cadinenes were also evaluated.
Subject(s)
Cyanides/chemistry , Cyanides/chemical synthesis , Naphthalenes/chemistry , Naphthalenes/chemical synthesis , Sesquiterpenes/chemical synthesis , Animals , Cyanides/pharmacology , Cyclization , Magnetic Resonance Spectroscopy , Naphthalenes/pharmacology , Optical Rotation , Polycyclic Sesquiterpenes , Sesquiterpenes/chemistry , Sesquiterpenes/pharmacology , Stereoisomerism , Thoracica/drug effectsABSTRACT
The first enantioselective total synthesis of 10-isocyano-4-cadinene, a marine sesquiterpene isolated from nudibranchs of the family Phyllidiidae, was achieved. The cadinene is expected to be a novel nontoxic antifouling agent. In the synthesis, an intermolecular Diels-Alder reaction and a SmI(2)-induced Barbier-type reaction were employed as key steps. The absolute configuration of 10-isocyano-4-cadinene was determined to be (1S, 6S, 7R, 10S) on the basis of the total synthesis. Antifouling activities against Balanus amphitrite with both enantiomers of 10-isocyano-4-cadinene were also evaluated.