Mn(III)-promoted annulation of enol ethers and esters to fused or spiro 2-cyclopentenones
作者:E.J. Corey、Arun K. Ghosh
DOI:10.1016/s0040-4039(00)95679-x
日期:1987.1
Manganese(III)-promoted addition of various 1,3-dicarbonyl compounds to enol ethers or terminal enolesters, followed by hydrolysis of the resulting adducts and base catalyzed aldol cyclization provides an effective process for the synthesis of a wide range of fused and spiro 2-cyclopentenones.
A Ring Closing Metathesis Based Approach for the Spiroannulation of Cyclopentanes and Cyclohexanes. Formal Synthesis of (±)-Acorones
作者:A. Srikrishna、M. Srinivasa Rao、Santosh J. Gharpure、N. Chandrasekhar Babu
DOI:10.1055/s-2001-18743
日期:——
An efficient ring closing methathesis (RCM) reaction based approach was developed for the spiroannulation of cyclopentanes and cyclohexanes and its utility demonstrated in the formal synthesis of the spirosesquiterpenes acorones.
A new synthesis, including asymmetric synthesis, of spiro[4.n]alkenones from three components: cyclic ketones, chloromethyl p-tolyl sulfoxide, and acetonitrile; and a formal total synthesis of racemic acorone
synthesized from several kinds of cyclic ketones and chloromethyl p-tolyl sulfoxide in good yields. Treatment of the 1-chlorovinyl p-tolyl sulfoxides with cyanomethyllithium at −78°C to room temperature gave spirocyclic enaminonitriles in high yields. Acidic treatment of the enaminonitriles afforded spiro[4.n]alkenones in good yields. By using an unsymmetrical cyclic ketone, α-tetralone, and optically active
Compounds and pharmaceutically acceptable salts of the compounds are disclosed, wherein the compounds have the structure of Formula (I) as defined in the specification. Corresponding pharmaceutical compositions, methods of treatment methods of synthesis, and intermediates are also disclosed.
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.