Diacetone Glucose Derived Dienes in Diels-Alder Reactions. Products and Transformations

Article abstract of DOI:10.1021/jo00224a024

Diene 2 which is readily prepared from diacetone glucose undergoes Diels-Alder reaction with maleic anhydride in a completely stereoselective manner to give compound 3 as the sole product.Subsequent hydrogenation of the double bond is also stereoselective and affords the cis-cyclohexanofurano ring junction.Sodium borohydride reduction of the anhydride 4 is chemoselective and lactone 7 is produced.The apparent anomalous reduction of the less-hindered carbonyl is rationalized by a chelation postulate.Diels-Alder reaction of the dienic alcohol 8a is equally selectiveand the primary product, 12, undergoes intramolecular trans acylation to afford 10a directly.DIBAL reduction of the lactonic ester, 10b, occurs preferentially at the lactone, and the acetal 13a is the product.The double bond of 13a resisted hydrogenation; however, if the rings were uncoupled with base and the hydrogenation carried out in the basic solution, the lactone 16a was obtained in excellent yield.The lactonic ester 10b reacts at the lactone carbonyl preferentially with Grignard reagents to give caged ketal lactones, e.g., 13b, 13c, and 13d.The "cage" in these molecules can be unravelled by treatment with alkali and reduction with sodium borohydride.Experiments have been carried out for giving access to the various groups in these condensed polyfunctional systems.