51352-68-2Relevant articles and documents
Synthesis of highly substituted γ-butyrolactones by a gold-catalyzed cascade reaction of benzyl esters
Jaimes, Maria Camila Blanco,Ahrens, Alexander,Pfl?sterer, Daniel,Rudolph, Matthias,Hashmi, A. Stephen K.
supporting information, p. 427 - 433 (2015/02/18)
Easily accessible benzylic esters of 3-butynoic acids in a gold-catalyzed cyclization/rearrangement cascade reaction provided 3-propargyl γ-butyrolactones with the alkene and the carbonyl group not being conjugated. Crossover experiments showed that the formation of the new C-C bond is an intermolecular process. Initially propargylic-benzylic esters were used, but alkyl-substituted benzylic esters worked equally well. In the case of the propargylic- benzylic products, a simple treatment of the products with aluminum oxide initiated a twofold tautomerization to the allenyl-substituted g-butyrolactones with conjugation of the carbonyl group, the olefin, and the allene. The synthetic sequence can be conducted stepwise or as a one-pot cascade reaction with similar yields. Even in the presence of the gold catalyst the new allene remains intact.
SYNTHESIS OF 5-ALKYL-3H-THIOLEN-2-ONES AND 5-ALKYL-3H-FURAN-2-ONES AND CONDENSATION REACTIONS AT THE HETEROCYCLIC METHYLENE GROUP
Sedavkina, V. A.,Morozova, N. A.,Egorova, A. Yu.,Ostroumov, I. G.
, p. 377 - 380 (2007/10/02)
The intramolecular cyclization of γ-ketocarboxylic acids and their esters gives 5-alkylsubstituted 3H-thiolen-2-ones and 3H-furan-2-ones.It was shown that reaction occured at the heterocyclic methylene group and that the conditions under which the reaction took place depended on the nature of the heterocyclic atom.
