Document Details Document Type : Article In Journal  Document Title : Organocatalysis for the Acid-Free O-Arylidenation of Carbohydrates Organocatalysis for the Acid-Free O-Arylidenation of Carbohydrates   Document Language : English  Abstract : Methyl glycopyranosides of glucose, galactose, and mannose, their 2,3-di-O-benzyl-protected derivatives, as well as the unprotected sugars react with p-methoxybenzaldehyde dimethyl acetal (3) and with benzaldehyde dimethyl acetal (7) as reagents in the presence of thiourea 1 or squaramide 2 as the organocatalyst to afford regioselectively 4,6-O-arylidenated derivatives 5 and 8. With an excess amount of 3 or 7, diarylidenated derivatives are also obtained. In situ formation of acetals of type 3 and 7 from corresponding aldehydes 10 and 13 in the presence of an orthoester and organocatalyst 1 or 2 can be used to generate 5 and 8 directly from the aldehydes. Some substrates also lead to mixed orthoesters with this procedure. The reaction courses are discussed.  ISSN : 1434-193X  Journal Name : EUROPEAN JOURNAL OF ORGANIC CHEMISTRY  Volume : 2013  Issue Number : 31  Publishing Year : 1434 AH 2013 AD  Article Type : Article  Added Date : Wednesday, July 19, 2017  Researchers Researcher Name (Arabic) Researcher Name (English) Researcher Type Dr Grade Email y Geng Geng, y Researcher     H Faidallah Faidallah, H Researcher     H Albar Albar, H Researcher     I mkhalid mkhalid, I Researcher     R Schmidt Schmidt, r Researcher     Files File Name Type Description  42105.pdf pdf   Back To Researches Page