82732-35-2Relevant academic research and scientific papers
A New Strategy for the α-Vinylation of Ketones : Application to an Enantioselective Synthesis of Sesquiterpene (+)-α-Elemene
Mehta, Goverdhan,Acharyulu, Palle V. R.
, p. 601 - 612 (2007/10/03)
A new, simple and preparatively useful protocol for the construction of α-vinyl ketones, particularly those bearing a quaternary carbon centre, from the corresponding alkenes has been devised. Our four-step strategy consists of dichloroketene addition, base catalysed ring contraction to 'push-pull' cyclopropane esters, reduction and eliminative cyclopropane fragmentation to unravel the α-vinyl ketone moiety. The generality of this approach has been demonstrated with a few representative olefins and good regio- and stereocontrol has been observed. As an application of this methodology, an enantioselective synthesis of sesquiterpene hydrocarbon (+)-α-elemene (42) from R-(+)-limonene (43) has been accomplished.
Synthesis of 1-Substituted cis-Bicyclooctanones through Cycloadditions of Dichloroketene to Alkenes. Structural Characterization of Cycloadducts by Oxa-Ring Expansion
Jeffs, Peter W.,Molina, Gerado,Cass, Malcom W.,Cortese, Nicholas A.
, p. 3871 - 3875 (2007/10/02)
The cycloaddition of dichloroketene to a series of 1-substituted cyclohexanes is shown to proceed in a highly regio- and stereospecific manner.The structures of the cycloadducts were determined by reductive dechlorination to the cyclobutanones, and the structures and stereochemistry of the latter as cis-bicyclooctan-7-ones (4) were established by an oxa-ring expansion to the corresponding cis-octahydrobenzofuran-2-ones (6).The structures of the lactones 6 were established by 1H and 13C NMR studies which further indicated that these compounds exist in conformation 6a rather than 6b.The success of the regio- and stereospecific cycloaddition of dichloroketene to the 1-substitutd cyclohexenes discussed is found to be critically dependent on utilizing the zinc dehalogenation procedure for its in situ generation.Additional examples of the cycloaddition of dichloroketene to indene, 1,4,-dihydronaphthalene and 1,2-dihydronaphthalene is also presented.
