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Pyrrolidines tertiary amine conjugates

Among several organocatalysts derived from L-proline (1) as a chiral source, pyrrolidine-tertiary amine conjugates constitute a powerful and useful family in asymmetric synthesis [115]. In 1994, Kawara and Taguchi reported pioneering work on the use of such catalysts in asymmetric Michael addition reactions [116]. Since then, several related catalysts have been developed. Figure 1.5 lists representative examples. [Pg.8]

Saturated heterocycles containing five or more atoms have physical and chemical properties typical of acyclic compounds that contain the same heteroatom. For example, pyrrolidine, piperidine, and morpholine are typical secondary amines, and A-methylpyrrolidine and quinuclidine are typical tertiary amines. The conjugate acids of these amines have pK values expected for ammonium ions. We have seen that the basicity of amines allows them to be easily separated from other organic compounds (Chapter 1, Problems 70 and 71). [Pg.886]

Michael/Henry/dehydration/aromatisation reaction of 2-(2-oxoethyl) benzal-dehydes and nitroalkenes mediated by pyrrolidine to obtain polysubstituted naphthalene derivatives. DBU catalysed the conjugate additions of alcohols to ot,p-unsaturated nitriles, esters and ketones. Perhaps more important are the aza-Michael addition reactions of amines to a,p-unsaturated ketones, nitriles and esters. Recently, Costa, Vilarrasa and coworkers described the addition of lactams, imides, 2-pyridone, pyrimidine-2,4-diones and inosines to methyl propiolate and other similar compounds, DABCO and DMAP being the best catalysts. As mentioned before, tertiary amines give zwitterionic species with activated allynes. It was as early as 1932 when Diels and Alder used the reaction of pyridine with dimethyl acetylenedicarbojylate (DMAD) for the synthesis of heterocycles. The interception of the corresponding intermediate with Al-tosylimines and activated olefins provided access to l-azadienes ° and highly substituted butadienes (Scheme 2.6). When the quenching species of the zwitterionic intermediate is a 1,2-diketone, dibenzoyl maleates or cyclopentenedione derivatives could be obtained (Scheme 2.6). The interception of the zwitterionic species of N-methyl imidazole (NMI) and DMAD with ketenes to obtain unsaturated esters has also been shown. ... [Pg.16]

The addition of nitroalkanes to chalcones is more attractive since the Michael adducts are useful intermediates for a variety of further elaborated stmctures such as chiral aminocarbonyls, pyrrolidines, y-lactams, and y-amino acids. Thus, many elegant organocatalysts such as cinchona alkaloid-derived chiral tertiary amine thiourea 69 [67] or suqaramide 70 [68] and bisquaternary ammonium salts [69] 71a or 71b have been developed for such a reaction in recent years (Scheme 5.33). In addition, a,(3-unsaturated A -acylpyrroles [70] and 4-oxo-enoates [71] were also applicable in the highly enantioselective conjugated addition with nitroalkanes (Scheme 5.34). [Pg.167]


See other pages where Pyrrolidines tertiary amine conjugates is mentioned: [Pg.218]    [Pg.324]    [Pg.709]    [Pg.78]    [Pg.1027]   
See also in sourсe #XX -- [ Pg.8 ]




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Amine conjugating

Amines tertiary

Amines tertiary conjugates

Conjugation amine

Pyrrolidine amine

Pyrrolidines amines

Tertiary conjugates

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