New supramolecular host systems. 5. Diacetals and macro-m-cyclophanes of aldaric esters: Synthesis, stereochemistry and conformational analysis

✍ Scribed by Harald Jatzke; Klaus Frische; Moshe Greenwald; Larisa Golender; Benzion Fuchs

• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 779 KB
• Volume: 53
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(97)00165-8

✦ Synopsis

A general scheme of carbohydrate diacetal systems (Scheme 2) of the 1,3,5,7-tetraoxadecalin (TOD) type is presented.. A sequence of reactions starting with dimethyl D-glucarate (4) (Scheme 3) lead to 2,6-diawI-4,8-di (methox2ccarbonyl)-cis-TOD podands (5 and 6) and to the novel dicarbamate macrocycles (8a,b), which constitute the first m-cyclophanes in the carbohydrate (D-gluco) series. The D-gluco -L-ido interconversion by equilibration of the methoxycarbonyl groups in 5, 6 and 9, was examined in the light of a conformational analysis of the methox3,carbonyl group and its anomeric effect in heterocyclic systems, using molecular mechanics techniques (MM3-GE. i.e., MM3 reparametrized for lreaBnenl of the gauche effect) and comparing with experimental data.