Acyclic tertiary amines

TABLE 4. nn ionization potentials (eV) of acyclic tertiary amines R3N... 

However, in more complicated amines, this straight correlation is violated. The bicyclic tertiary amine l-azabicyclo[4.4.4]tetradecane (22) and the acyclic tertiary amine n-Bu3N have nearly the same first IP (7.84 and 7.90 eV, respectively), but the proton affinity of the bicyclic amine is 20 kcal mol 1 lower than that of the acyclic52. On the other hand, for other bridge-head tertiary amines like l-azabicyclo[2.2.2]octane (quinuclidine, 20) and l-azabicyclo[3.3.3]undecane (manxine, 21) the expected relation between proton affinities and IP values is observed. The extraordinary properties of l-azabicyclo[4.4.4]tetradecane (22) are caused by its unusual conformation the nitrogen lone-pair is directed inward into the bicycle where protonation is not possible. In the protonated form, the strained out-conformation is adopted. This makes it the least basic known tertiary amine with purely saturated alkyl substituents. Its pKa, measured in ethanol/water, is only +0.693. Strain effects on amine basicities have been reviewed by Alder88. 

Preparative Methods the title reagent is prepared by the treatment of (IR, 25)-(—)-norephedrine with 1,4-dibromo-butane and NaHCOs in toluene. This approach can be modified to form a wide variety of cyclic and acyclic tertiary amine derivatives. The enantiomeric reagent has also been formed from (+)-norephedrine. 

The effect of cyanogen bromide on acyclic tertiary amines is to remove the smallest w-alkyl group (up to w-hexyl) as alkyl bromide in reaction (a). This reaction usually leads to the alkyl bromide that most readily exchanges its bromine thus, when R is allyl or benzyl it readily appears as the bromide RBr, but when R is phenyl this is not so. The quaternary ammonium bromide is obtained as by-product, by reaction of the RBr with the tertiary amine used,... 

TERTIARY AMINES Acyclic tertiary amines Pyrrolizidines Phenanthroindolizidines Phenanthroquinolizidines Harringtonine and isoharringtonine Dimeric tetrahydroisoquinolines Dimeric indole alkaloids... 

Pappalardo, J.A. The Acyclic Aliphatic Tertiary Amines Macmillan NY, 1965, p. 14. 

The reactions of boron trifluoride adducts of ammonia,and primary, secondary, and tertiary amines with phosphorus pentachloride have been studied and in the first two cases acyclic phosphazenes were obtained. With the ammonia-adduct, a previously characterized phosphazene salt was obtained ... 

Compounds belonging to this series are of special interest because they exhibit the properties of both cyclic and acyclic structures as a result of ion complex tautomerism. They were obtained via borylation of hydroxy-alky lphosphines in the presence of tertiary amines [Eq. (64)], whereas primary and secondary amines give aminomethylphosphines under such conditions (84UK625 86JZV1641, 86MI1 90MI1). 

Preliminary mechanistic studies show no polymerization of the unsaturated aldehydes under Cinchona alkaloid catalysis, thereby indicating that the chiral tertiary amine catalyst does not act as a nucleophilic promoter, similar to Baylis-Hilhnan type reactions (Scheme 1). Rather, the quinuclidine nitrogen acts in a Brpnsted basic deprotonation-activation of various cychc and acyclic 1,3-dicarbonyl donors. The conjugate addition of the 1,3-dicarbonyl donors to a,(3-unsaturated aldehydes generated substrates with aU-carbon quaternary centers in excellent yields and stereoselectivities (Scheme 2) Utility of these aU-carbon quaternary adducts was demonstrated in the seven-step synthesis of (H-)-tanikolide 14, an antifungal metabolite. 

The scope of Michael additions with catalysts containing cyclohexane-diamine scaffolds was broadened by Li and co-workers [95]. When screening for a catalyst for the addition of phenylthiol to a,p-nnsatnrated imides, the anthors fonnd that thiourea catalyst 170 provided optimal enantioselectivities when compared to Cinchon alkaloids derivatives (Scheme 41). Electrophile scope inclnded both cyclic and acyclic substrates. Li attributed the enantioselectivity to activation of the diketone electrophiles via hydrogen-bonding to the thiourea, with simultaneous deprotonation of the thiol by the tertiary amine moiety of the diamine (170a and 170b). Based on the observed selectivity, the anthors hypothesized that the snbstrate-catalyst... 

A -Unsubstituted 1,2,4-diazaphospholes (4) undergo A -alkylation by reaction with alkyl vinyl ether, sulfur ylides, and diazo compounds <95HAC403>. They react with acyl chlorides in a 2 1 molar ratio to give a mixture of the A -acylated diazaphosphole and the diazaphosphole hydrochloride. Preparative A -acyclation is achieved in presence of a tertiary amine. Sulfonyl chlorides and phosphorus trichloride also give A -substitution reactions (Scheme 2) <87TH 422-01 >. 

For reviews of this reaction, sec Gibson, in Patai, Ref. 355, pp. 45-55 Spiallcr Pappalardo The Acyclic Aliphatic Tertiary Amines Macmillan New York. 1965, pp. 14-29. 

Reduction of aldehydes and ketones. Earlier work on amine borane reagents was conducted mainly with tertiary amines and led to the conclusion that these borane complexes reduced carbonyl compounds very slowly, at least under neutral conditions, and that the yield of alcohols is low. Actually complexes of borane with primary amines, NHj or (CH3)3CNH2, reduce carbonyl compounds rapidly and with utilization of the three hydride equivalents. BH3 NH3 is less subject to steric effects than traditional complex hydrides. A particular advantage is that NH3 BH3 and (CH3)3CNH2 BH3 reduce aldehyde groups much more rapidly than keto groups, but cyclohexanone can be reduced selectively in the presence of aliphatic and aromatic acyclic ketones. 

L. Spialter and J. A. Pappalardo, The Acyclic Aliphatic Tertiary Amines , Macmillan, New York, 1965. 

L. Spialter and J. A. Pappalardo, The Acyclic Aliphatic Tertiary Amines, Macmillan, New York (1965) Chemistry of the Amino Group, Ed. S. Patai, Interscience, New York (1968)... 

Descriptors (Acyclic + Phosphoric acids + Tertiary amines) (Model 75)... 

For aliphatic chemicals with phosphoric acid or a tertiary amine, the Acyclic Aliphatic + ( 75) model should be used, which consists of the following equation ... 

Acyclic Aliphatic+ Model 75 for Phosphoric Acid and Tertiary Amine. 

The alkylation of asymmetric acyclic ketones takes place regioselectively on the most-substituted carbon, thus affording the syn isomers as major products. a-Hydroxyketones showed anti selective additions similar to that observed in related aldol, and Mannich-type additions (Scheme 2.39). Such selectivity is due to the preferred formation of the Z-enamine intermediate, stabilized by intramolecular hydrogen bonding between the hydroxy group and the tertiary amine of the catalyst [23]. 

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