Diversity-oriented synthesis of enantiopure furofurans from carbohydrates: An expedient approach with built-in michael acceptor, masked aldehyde and leaving group in a single sugar derivative

摘要

A single sugar molecule containing three functional groups, namely a masked aldehyde, a Michael acceptor and a leaving group, reacts with a series of β-dicarbonyl compounds and related reagents to form up to three new bonds and up to three new stereocenters. The configuration of the sugar derivative controls the diastereoselectivity in the formation of all the new bonds without a requirement for any external reagent for asymmetric induction. This "Chiral pool" based diversity-oriented synthetic strategy has led to the formation of a series of furofurans based on different scaffolds and with appendage variations, and also to a hitherto unknown family of bicyclic 3,8-dioxabicyclo[4.2.1]nonanes. A single sugar molecule consisting of a masked aldehyde, a Michael acceptor, and a leaving group is capable of reacting with β-dicarbonyl compounds and related reagents to form enantiopure furo[2,3-b]furans via 3,8-dioxabicyclo[4.2.1]nonane intermediates in some cases. Three centers in the sugar molecule, namely C-1, C-2, and C-5, were usedboth in a sequential and a one-pot fashion.