A general and simple methodology for spirocyclopentannulation of cyclic ketones (or 4,4-disubstituted cyclopentenones from acyclic ketones) and its application in the synthesis of the spirodienone via a prochiral precursor constituting a formal totalsynthesis of (±)-acorone (), are described.
Claisen Rearrangement Based Methodology for the Spiroannulation of a Cyclopentane Ring. Formal Total Synthesis of (±)-Acorone and Isoacorones
作者:A Srikrishna、P Praveen Kumar
DOI:10.1016/s0040-4020(00)00743-2
日期:2000.10
A Claisen rearrangement based methodology for spiroannulation of a cyclopentane ring to cyclic precursors and its application in the formal total synthesis of acorones 1 is described. Thus, Claisen rearrangement of 2-cycloalkylideneethanols 12 with 2-methoxypropene and a catalytic amount of mercuric acetate generates 4,4-substituted hex-5-en-2-ones 13. Ozonolytic cleavage of the terminal olefin in the enones 13 and intramolecular aldol condensation of the resulting keto-aldehydes 14 furnishes the spiroannulated compounds 15. (C) 2000 Elsevier Science Ltd. All rights reserved.