Hammett correlations imines

These observations, along with kinetic isotope effect studies and Hammett correlation studies, support a concerted elimination by a-bond metathesis involving a four-membered transition state (Eq. 2) [23]. A large kinetic isotope effect is observed for the loss of methane from methyl amide complexes lb and lh (Eqs. 3 and 4), comparable to those observed by Buchwald and coworkers for formation of zirconium rj2-thioaldehyde complexes [25] and by Bercaw and coworkers for formation of tantalum rf- imine complexes [5a] through similar transition states. 

The efficient enantioselective alkylation of the P/y-unsaturated ester 39 was achieved1351 by use of the N-anthracenylmethyl catalyst 12 (R=benzyl, X=Br) together with CsOH-H20 under phase transfer conditions analogous to those in the alkylation of the O Donnell imine 23, as shown in Scheme 13. The enantioselectivity of the alkylation correlates with Hammett o constants, and the N,N-dimethylamino substituents in 39 showed the most effective enantioselectivity. The tight ion pair in which the enolate... 

H and, 3C NMR spectra of monoimines have been reported and are shown in Table 3. These data fit the Hammett relationship and good correlations are found between various o constants and, 3C chemical shifts at positions remote from the substituent.1413C chemical shifts of imines derived from BA and variously substituted benzylamines are affected by substituents through up to 11 bonds.15 The influence of ZjE isomerism (Figure 3) and the effect of substituents on NMR spectra of some unsaturated imines have been studied.16 The photochemically induced isomerization of several substituted Schiff bases derived from BA and arylamines and their chemical shifts, as well... 

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