- Synthesis of chiral azamacrocycles using the bis(α-chloroacetamide)s derived from chiral 1,2-diphenylethylenediamine
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Optically active diphenyl-substituted tetraaza-12-crown-4 diamide (10), tetraaza-15-crown-5 diamide (12), tetraaza-18-crown-6 diamide (11), and hexaaza-18-crown-6 diamide (9) ligands were prepared by treating the appropriate secondary diamines with the (R,R)- and (S,S)- forms of 1,2- bis(N-methyl-α-chloracetamido)-1,2diphenylethane (20). Macrocyclic diamides 9 and 10 were reduced to form the optically active diphenyl-substituted hexaaza-18-crown-6 (13) and tetraaza-12-crown-4 (14), respectively. Reduction of macrocyclic diamide ligands 11 and 12 gave a complex mixture of products from which the desired tetraaza-15-crown-5 and 18-crown-6 compounds could not be isolated. Dichloride 20 was prepared by treating the chiral forms of 1,2- diphenylethylenediamine with chloroacetic anhydride or chloroacetyl chloride. The crystal structures for the (R,R)-form of dichloride 20 and the (S,S)-forms of macrocycles 10 and 11 are reported.
- Hu, Kejiang,Krakowiak, Krzysztof E.,Bradshaw, Jerald S.,Dalley, N. Kent,Xue, Guoping,Izatt, Reed M.
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- Diastereoselective Cycloaddition of N-Lithiated Azomethine Ylides to (E)-α,β-Unsaturated Esters Bearing a C2-Symmetric Imidazolidine Chiral Controller
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The 1,3-dipolar cycloaddition of N-metalated ylides to chiral (E)-3-(1,3-disubstituted 4,5-diphenylimidazolidin-2-yl)propenoates proceeded highly diastereoselectively.The previously unknown absolute configuration of optically pure 1,2-dianilino-1,2-diphenylethane was determined from the absolute configuration of the cycloadducts.What diastereotopic olefin face of the α,β-unsaturated ester was attacked by the ylide was found to depend dramatically upon the nature of N substituents of the chiral controller as well as upon the bulkiness of the ester moiety of the ylide.
- Kanemasa, Shuji,Hayashi, Takeshi,Tanaka, Junji,Yamamoto, Hidetoshi,Sakurai, Tosio
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p. 4473 - 4481
(2007/10/02)
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