1489-50-5Relevant articles and documents
Transition Metal- and Acid-Induced Transformations of 6-Siloxy-Substituted 5,6-Dihydro-4H-1,2-oxazines: Preparation of Pyrroles, Nitrones, 1,4-Dicarbonyl Compounds and Derivatives Thereof
Hippeli, Claudia,Zimmer, Reinhold,Reissig, Hans-Ulrich
, p. 469 - 474 (2007/10/02)
A variety of 6-siloxy-substituted 5,6-dihydro-4H-1,2-oxazines (abbreviation: 1,2-oxazines) 1, 3 could be transformed into di- and trisubstituted pyrroles 2, 4 by means of molybdenum hexacarbonyl.The mechanism of this deoxygenating ring contraction is discussed.With two bicyclic 1,2-oxazines an acid-catalyzed fragmentation affording α-methylenecycloalkanones 7 has been observed, while other 1,2-oxazines rearrange in methanolic acid to give nitrones 9, 10.The desilylation of 6-siloxy-substituted 1,2-oxazines 1.3 employing NEt3*3HF is a very general and smooth process providing 6-hydroxy-1,2-oxazines 11, 12 or their corresponding acyclic tautomers 13, 14 in high yields.For two examples of 11 deoximations by use of formalin could be achieved with moderate efficiency giving 1,4-dicarbonyl compounds 15.
PREPARATION OF α-METHYLENE KETONES BY THE PALLADIUM-CATALYZED DECARBOXYLATION-DEACETOXYLATION OF ALLYL α-ACETOXYMETHYL-β-KETO CARBOXYLATES UNDER MILD CONDITIONS
Tsuji, Jiro,Nisar, Mohammad,Minami, Ichiro
, p. 2483 - 2486 (2007/10/02)
α-Methylene ketones are prepared in high yields by the palladium-catalyzed decarboxylation-deacetoxylation of allyl α-acetoxymethyl-β-keto carboxylates.The reaction proceeds rapidly at room temperature under neutral conditions in acetonitrile.
