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Dimethylformamide dimethylacetal (DMFDMA) is widely used as a source of electrophilic one-carbon units at the formate oxidation level; however, electrophilic methylation with this reagent is previously unreported. Reaction of anthranilamide with DMFDMA at 150 °C for short periods gives mainly quinazolin-4-one. However, prolonged reaction with dimethylformamide di(primary-alkyl)acetals leads to subsequent alkylation at N(3). 3-Substituted anthranilamides give 8-substituted 3-alkylquinazolin-4-ones. Condensation of anthranilamides with dimethylacetamide dimethylacetal provides 2,3-dimethylquinazolin-4-ones. In these reactions, the source of the N(3)-alkyl group is the O-alkyl group of the orthoamides. By contrast, reaction with the more sterically crowded dimethylformamide di(isopropyl)acetal diverts the alkylation to the oxygen, giving 4-isopropoxyquinazolines, along with N(3)-methylquinazolin-4-ones where the methyl is derived from N-Me of the orthoamides. Reaction of anthranilamide with the highly sterically demanding dimethylformamide di(t-butyl)acetal gives largely quinazolin-4-one, whereas dimethylformamide di(neopentyl)acetal forms a mixture of quinazolin-4-one and N(3)-methylquinazolin-4-one. The observations are rationalised in terms of formation of intermediate cationic electrophiles (alkoxymethylidene-N,N-dimethylammonium) by thermal elimination of the corresponding alkoxide from the orthoamides. These are the first observations of orthoamides as direct alkylating agents.

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1992 stereochemistry stereochemistry (general, optical resolution) O 0030 26 -053 Enantioselective Conjugate Addition with Chiral Amidocuprates. Part 3. Studies on the Synthetic Optimization of Mapp-Cuprates. -The influence of Cu(I) salt, solvents, Tms-Cl and ligand e.e. on the reactivity and selectivity of cuprate (I) in the conjugate addition to 2-cycloheptenone (II) is investigated (22 entries). The best result is obtained under the conditions shown in the scheme. -(ROSSITER, B. E.; MIAO, G.; SWINGLE, N. M.; EGUCHI, M.; HERNANDEZ, A. E.; PATTERSON, R. G.; Tetrahedron: Asymmetry 3 (1992) 2, 231-234; Dep. Chem., Brigham Young Univ., Provo, UT 84602, USA; EN)

1993 stereochemistry stereochemistry (general, optical resolution) O 0030 -061Enantioselective Conjugate Addition to Cyclic Enones with Scalemic Lithium Organo(amido)cuprates. Part 4. Relationship Between Ligand Structure and Enantioselectivity.-Lithium organo(amido)cuprates prepared in situ undergo enantioselective addition to cyclic enones. The outcome depends strongly on the structure of the amine ligand as well as on the copper and lithium components and the solvent used. Best results are obtained using (S)-N-methyl-1-phenyl-2-(1-piperidinyl)ethanamine as ligand. -(ROSSITER, B. E.; EGUCHI, M.; MIAO, G.; SWINGLE, N. M.; HERNANDEZ, A. E.; VICKERS, D.; FLUCKIGER, E.; PATTERSON, R. G.; REDDY, K. V.; Tetrahedron 49 (1993) 5, 965-986; Dep. Chem., Brigham Young Univ., Provo, UT 84602, USA; EN)