Dimethylamino precursor

The ABCD ring system of the diterpene alkaloid atisine was constructed by T. Kametani et al using an intramolecular Diels-Alder cycloaddition reaction as the key step. The dienophile was obtained by the traditional Hofmann degradation of the corresponding dimethylamino precursor. The diene was prepared by the kinetic enolization of the cyclohexenone system with LDA. 

MOCVD Reactions. A great deal of interest has been generated by the availability of two metallo-organic titanium compounds, tetrakis-diethylamino titanium (TDEAT) andtetrakis-dimethylamino titanium (TDMAT). These precursors make possible the deposition of TiN at lower temperature.[ " k l These compounds are liquid at room temperature. A flow of helium bubbling through the warm precursor entrains the vapor into the deposition chamber. Deposition temperature is approximately 320°C. The following reactions occur ... 

Hexacoordinate spirocyclic phosphorus compounds have been prepared in which the spirocyclic system involves dative bonds from the dimethylamino-l-naphthyl ligand <1996JOM173, 1997PS181, 1999IC1336> for example 113 (Equation 29). Spirophosphoranide 122 was synthesized by deprotonation of the acid precursor 121 with triethyl-amine (Equation 30) <2001IC6229, 2002IC1645>. 

There have been few alternative indium precursors studied. They include intramolecular adducts such as l,3-[(dimethylamino)propyl]dimethylindium, [Me2N(CH2)3InMe2]125,126 (Figure 20a with R,R = Me). 

Another example has been provided by Ito et al., who described the use of methanofullerene derivatives as powerful and stable precursors for glycofullerenes.217 Their study was based on the use of [60]fullerenoacetyl chloride (227), obtained from the ferf-butyl [60]fullerenoacetate derivative 226, which had been prepared in 56% yield by treatment of corresponding stabilized sulfonium ylides 225 with C6o-218 Subsequent transformation with p-TsOH in toluene gave [60]full-erenoacetic acid, which was directly converted into the corresponding acyl chloride 227 by using thionyl chloride. Standard ester formation with methyl 2,3,4-tetra-O-benzyI -/<-d-gl ucopyranoside (228) and 4-(dimethylamino)pyridine (DMAP) afforded the desired hybrid derivative 229 in 66% yield. 

In order to rationalize the factors determining the enantioselectivity of the hydrosilylation of the para-substituted styrenes, we have calculated the relative thermodynamic stabilities of all the intermediates of the catalytic cycle that are precursors of the two enantiomeric products as a function of the para-substituted substrates. Since, the 5 configuration product was formed in 64% ee from styrene, whereas 4-(dimethylamino)styrene afforded the R product with 64% ee [6], we have performed all calculations with these two different substrates. We shall demonstrate, in fact, that the relative thermodynamic stabilities of the fi3-allylic complexes are decisive for both the regio and the stereoselectivity. 

Yamaguchi et al. also reported the use of another new Cp Ir NHC complex 9 bearing basic 2-(dimethylamino)ethyl group in a Cp ring as the catalytic precursor in Oppenauer-type oxidation (Scheme 5.7) [34]. Owing to the basic amino... 

In the majority of pentatetraenylidene complexes prepared or generated so far, the pentatetraenylidene ligand is derived from suitable C5 precursors. Usually penta-1,3-diynyl derivatives like the alcohol HC = C—C = C—CPh20H, its trimethylsilyl ether, or the 5,5,5-tris(dimethylamino)-substituted penta-l,3-diyne are employed. 

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