Carbon-nitrogen double bond, 372 Table

Fry and Newberg 1,2> examined the electrochemical reduction of nor-camphor oxime (109) and camphor oxime (110) to the corresponding amines. The results of this study are shown in Table 3. It is clear from a comparison of these data with those in Table 2 that the electrochemical reduction of oximes 109 and 110 takes a very different stereochemical course from reduction of the corresponding anils 103 and 104. Reduction of oximes apparently proceeds under kinetic control, affords products corresponding to protonation at carbon from the less hindered side of the carbon-nitrogen double bond, and affords the less stable epimeric amine in each case. It is not evident why the stereochemistry of reduction of anils and oximes should differ, however. 

The 3,4-dihydroisoquinoline system is also encountered in this family of alkaloids. The assignment of chemical shifts to the aromatic carbon atoms of the substituted 3,4-dihydroisoquinolines (21-25 in Fig. 3 and Table III) followed directly from the application of the appropriate substituent parameters to the shifts reported for 20 (22) and from a consideration of the resonance effect of the carbon-nitrogen double bond. This latter point is especially evident in the methiodide salts, 24 and 25, where charge delocalization causes C-4a, C-6, and C-8 to appear at lower field than their counterparts C-8a, C-l, and C-5, respectively. Carbon-1 was readily recognized as the lowest field resonance because of its imine character. 

Table I, examination of which provides ample support for the generality of the process. It is noteworthy that increased branching at the carbon a to the imine function leads to decreased yields of the desired adducts (12) the reason for this failure has not been addressed, but reversion by retroaldolization is one likely possibility. The base that was typically employed to effect the deprotonation of the intermediate aldimines was lithium diisopropylamide, since alkyllithiums were found to add to the carbon-nitrogen double bond of the aldimines. Wittig observed in a number of instances that the overall yields of a,3-un-saturated carbonyl compounds obtained according to this procedure were better than by the corresponding classical Wittig reaction. Interestingly, the anion derived from the r-butylimine of isobutyraldehyde reacts with selected a,3-unsaturated ketones to give 1,4-adducts, whereas the corresponding hydrazone anions add to such ketones to provide the 1,2-adducts. ...

Scheme 10.28. A repeat of Scheme 9.35. Here, Nu represents an amino function and the attack of the incoming group is drawn to be greater than 90° as suggested by Biirgi et al. (BUrgi, H. B. Dunitz, J. D. Shefter, E. J. Am. Chem. Soc., 1973,95,5065). Affirming the data in Table 10.4, the carbonylamines shown here generally lose water to produce compounds with carbon-nitrogen double bonds. See Scheme 10.29.

The facile addition of dichlorocarbenes to olefins under phase transfer conditions has also been observed with imines. The carbon-nitrogen double bond reacts with dichlorocarbene under conditions similar to those required for isolated alkenes. Thus, dichlorocarbene addition to C,N-diaryl substituted Schiff s bases afford good yields of l,3-diaryl-2,2-dichloroaziridines (Eq. 3.8). Hydrolysis of the C,N-diarylaziridines (IV) to the corresponding aryl-o -chloroacetanilides (V) is also reported (Eq. 3.9) and examples of both processes are recorded in Table 3.3. 

The influence of cyclopropyl on the gas phase stability of carbocations as measured by ion cyclotron resonance is shown in Table 14, along with data for some reference compounds. The results are given as gas phase basicities, GB, and proton affinities, PA, defined as AG° and AH°, respectively, for dissociation of the protonated molecule, as in equation 11. In addition hydride affinities D(BH H ) for some cations defined as — AH° for equation 18 are included. For the gas phase basicities and proton affinities the products B are alkenes, amines, nitriles or carbonyl compounds, and thus for these values the stability of the cation is compared to a derivative where the substituent is conjugated with a carbon-carbon or carbon-oxygen double bond, or a nitrogen lone pair, whereas for hydride affinities the products are saturated. 

This table is a partial listing of GC values available from the original Domalski-Hearing tables. Table-specific nomenclature Cd = carbon with double bond Ct = carbon with triple bond Cb = carbon in benzene ring Ca = allenic carbon corr = correction term Cbf = fused benzene ring Na = azo nitrogen Ni = imino nitrogen. 

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