Intramolecular diels-alder cycloadditions of substituted furfuryl E-2-(phenylsulfonyl)acrylates

✍ Scribed by Michael E. Jung; Vu Chi Truc

• Publisher: Elsevier Science
• Year: 1988
• Tongue: French
• Weight: 324 KB
• Volume: 29
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)82264-9

✦ Synopsis

Several substituted furfuryl E-2-(phenylsulfonyl)acrylates have been prepared by direct routes and cyclized in good yield under very mild conditions to give highly oxidized systems of potential use in natural products synthesis.

Recently there has been great interest in synthetic approaches to the avermectins and milbemycins2 due to the complexity of their structures and their potent biological activity, e.g., the derivative ivermectin 1 is a commercial anthelmintic agent with high potential for agriculture3 and use in human ophthalmic medicine.4 Numerous groups have published work aimed at the total'synthesis of these molecules and their substructures, the bicyclic acetal "top" portion and the hexahydro benzofuran "bottom" segment.5 We have been interested in a route to a highly functionalized synthon for the bottom half of these molecules based on an intramolecular Diels-Alder cycloaddition of an N-furfuryl acrylamide followed by a subsequent ring opening via reductive elimination.6 Due to difficulties associated with hydrolysis of tri-and tetracyclic lactams in this series, we decided to investigate an analogous route utilizing furfury