An efficient method for the one-pot synthesis of tetramic acid derivatives was developed utilizing tandem umpolung N-alkylation/reduction/cyclization of γ-hydrazono β-ketoester. By using this reaction as a key step, the total synthesis of the 3-spiro 7-hydroxamic acid tetralin which possesses an HDAC inhibitory activity was also achieved.
Regioselective addition of titanium enolates to 1-acylpyridinium salts. A convenient synthesis of 4-(2-oxoalkyl)pyridines
作者:Daniel L. Comins、Jack D. Brown
DOI:10.1016/s0040-4039(01)81368-x
日期:1984.1
Titanium enolates add to the 4-position of 1-phenoxycarbonylpyridinium salts to give 1,4-dihydropyridines; subsequent aromatization provides 4-(2-oxoalkyl)pyridines.
Reaction of organolithiums with a 1-(trimethylsilyl)ethenyl sulfide produces 1,2-bis(trimethylsilyl)cyclopropanes, while use of 1-silylethenyl sulfides bearing a bulkier silyl moiety results in exclusive formation of the corresponding Michael adduct anions which are then quenched with aldehydes to give vinyl sulfides. On the contrary, a 1-(trimethylsilyl)ethenyl sulfoxide undergoes smooth Michael addition with a variety of organo-metallics and the resulting carbanion intermediates can be quenched with aldehydes to produce vinyl sulfoxides. Scope and limitations of these sequential reactions are discussed.
and condensation of the chiral furaldimine with lithiumesterenolates has been examined. The product distribution of the reaction is dependent upon reaction conditions and on the kind of the substituent placed on the esters. Disubstituted esterenolate resulted in the exclusive formation of (4R)-beta-lactam, while unsubstituted, tert-butyl esterenolate preferentially gave (3R)-beta-amino ester. With
Several new α-phenyltelluro carbonyl compounds have been synthesized by the reaction of benzenetellurenyl iodide with lithium enolates derived from ketones, esters, and an amide in tetrahydrofuran at -78°C.