1-Methylindenes

The lithium-(-)-sparteine complex, generated by deprotonation of 1-methylindene, does not lose its configuration in diethyl ether solution even at room temperature80 presumably, the observed major diastcreonier is the thermodynamically determined product. Substitution with carbonyl compounds leads to 1-substituted (fl)-l-methyl-l//-indenes with >95% ee in high yields81. 

Matsson (1985) determined the secondary /3-deuterium KIE for the base-catalysed stereospecific 1,3-prototropic rearrangement (37) of 1-methylindene... 

Table 32 Primary and secondary j3-deuterium KIEs for the rearrangement of 1-methylindene to 3-methylindene using the rigid amines [8]—[11] as catalysts in toluene and DMSO at 20°C. ...

An alternative to evaluating the KIE and the rate constants from the above equations is to apply nonlinear least-squares fitting to the complete kinetic set of a and t values. This latter procedure has the advantage that errors in the reaction model, e.g. an incorrect mechanism, or extraneous data points are more easily discovered. This method was applied by Bergson et al. (1977) and Matsson (1985) in the determination of both the primary deuterium and secondary a-deuterium KIEs in the 1-methylindene rearrangement to 3-methylindene (reaction (67)). For example, a secondary /3-deuterium KIE of 1.103 0.001 was determined very accurately in toluene at 20°C using this method (Bergson et al., 1977). 

Methylindene undergoes rapid rearrangement to 3-methylindene [13] via the conjugate base, when treated with aqueous sodium hydroxide and benzyltriethyl-ammonium chloride under reaction conditions similar to those described in 9.4.1. 

Results of a theoretical study of 1,3-prototropic rearrangement of 1-methylindene, catalysed by ammonia and MesN in water and in cyclohexane, have confirmed earlier predictions that the proton moves freely over the indene ring once it has been abstracted by the base. The relative rates of deprotonation, ion-pair collapse and ion-pair rearrangement have been estimated and discussed in each case. 

Discussions to this point rely on the hypothesis that the ligands of oxo(salen)manganese(V) complexes have planar structures by analogy to metalloporphyrin complexes and Mn(III)-salen complexes 11 and 12, the structures of which were determined by the X-ray crystallographic analysis [29a,47]. However, the assumption that the ligand of the oxo-Mn-salen species is planar failed to give a satisfactory explanation for the following stereochemistry observed in the recent study. Trans-cis selectivity in the epoxidation of 1-alkylindenes usually improves as the steric bulk of the catalyst increases. However, the epoxidation of 1-methylindene with the smallest... 

SM2/AM1 and SM3/PM3 calculations in water as well as SM4/AM1 and SM4/PM3 calculations were performed on cyclohexane to study proton transfer reactions in 1-methylindene with two bases, ammonia and trimethylamine. The calculations confirmed predictions that the proton moves relatively freely over the indene ring once it is abstracted from the original location by the base [130]. 

Among the reactions on organomagnesium clusters, allyl isomerization of olefins seems to be the best-understood one at the present time. In the films containing magnesium and olefins, such as allylbenzene and 1-methylindene, multiple bond migration proceeds in very high yields. 

The isomerization of 1-methylindene to 3-methylindene proceeds analogously. The reaction starts in the solid film at 120-130 K, and the conversion of the initial reagent is completed at 230 K. It is evident that the specific features of the reactions of unsaturated compounds in the films of their cocondensates with magnesium point to a quite unique character of these processes, which combine an unconventional nature of the active site, high performance, and mild reaction conditions. 

Miura M, Fujisaka T, Nojima M, Kusabayashi S, McCullough KJ (1985) Ozonolysis of 1-methylindenes Solvent, temperature and substituent electronic effects on the ozonide exo/endo ratio J Org Chem 50 1504-1509... 

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