Method for iodination or bromination of carbon atom of alpha-methylene of secondary amide

PURPOSE: To obtain a new production method especially useful to produce α- iodoamide or α-bromoamide as an intermediate capable of easily giving an α,β-unsatd. amide by dehalogenation-dehydrogenation. CONSTITUTION: When the carbon atom of α-methylene of a sec. amide is iodinated or brominated, the sec. amide is allowed to react with a compd. represented by the formula R 3 Si-X (where X is I, Br or Cl and R is methyl, ethyl or n-propyl) in an aprotic org. solvent selected from among toluene, methylene chloride and THF in the presence of I 2 or Br 2 and a base selected from among N,N,N',N'-tetramethylethylenediamine(TMEDA), triethylamine (Et 3 N) and diethylmethylamine (Et 2 MeN) and the resultant iodinated or brominated product is isolated. COPYRIGHT: (C)1992,JPO