Total synthesis of dumsin. 1. Retrosynthetic strategy and the elaboration of key intermediates from (--)-bornyl acetate.
An intramolecular anionic oxy-Cope rearrangement (44 --> 46) serves as the key step in a synthetic approach to the insect antifeedant dumsin. Initial investigations clarified the manner in which (--)-bornyl acetate may be transformed into the exo-norbornenol 44. Two routes were developed to advance beyond 46. The first involved acetal 51 as a matrix that was expected to allow the elaboration of rings D and E. The second plan deferred oxidation of the cyclopentene ring in 46 to a later stage of molecular construction. The latter experiments formed the basis of a protocol that led to the successful acquisition of keto aldehydes typified by 108 and 114.
Paquette
Leo A
LA
Evans Chemical Laboratories, The Ohio State University, Columbus, Ohio 43210, USA. paquette.1@osu.edu
Hong
Fang-Tsao
FT
D000351:Africa, Eastern; D001892:Camphanes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010946:Plants, Medicinal / Q000737:chemistry; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism
D001892:Camphanes; D007202:Indicators and Reagents; C071528:bornyl acetate