1- Aryl-2-methyl cyclopentane

In 2008 Bhanage s team reported on a copper-catalyzed carbonylative Sonogashira reaction of aryl iodides [68]. In this procedure, copper bis(2,2,6,6-tetra-methyl-3,5-heptanedionate) [Cu(TMHD)2] was used as the catalyst for this transformation and using NEta as a base. Alkynones were produced in good yields (Scheme 5.33). A nickel-catalyzed carbonylation of allyl halides and acetylenes was reported on by Moreto and colleagues [69]. Cyclopentane skeletons were produced in high yields and with controlled stereochemistry. 

A condensation of vinyl sulphides of synthetic value involves the reaction of a-ethylthio-styrenes with an aldehyde in the presence of a Lewis acid catalyst to give 3-ethylthio-indenes. Regiospecific and stereospecific pentannelation i.e, fusion of a cyclopentane ring) of an alicyclic ketone involves arylthiomethylen-ation followed by base-catalysed addition to an aj8-unsaturated ester. a-Phenyl-thiobutenolides are less reactive Michael acceptors than their sulphoxide counterparts, and /SjS-dichlorovinyl sulphides are less reactive in electrophilic reactions than their oxygen counterparts. Dimerization of aryl a-cyanovinyl sulphides occurs more readily than that of alkyl analogues, since the intermediate 1,4-diradical ArSC(CN)CH2CH2d(CN)SAr, which cyclizes to the cyclobutane, is more stable. Products obtained by photolysis of methyl vinyl sulphide are accounted for by homolysis of both vinyl—S and methyl—S bonds. The kinetics of catalysed cis-trans isomerization of aryl vinyl sulphides have been studied. ... 

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