Stereoselective Tandem Cascade Furan Cycloadditions

Oligofurans linked by a rigid tether
undergo tandem cycloaddition
reactions with high stereoselectivity. The reaction of bisfurans with
dimethyl acetylenedicarboxylate (DMAD) involves tandem [4 + 2]/[4
+ 2] cycloadditions in a pincer mode. The reaction of oligofurans
with arynes involves stereoselective tandem [4 + 2]/[4 + 2] cycloaddition
reactions in a domino mode. The corresponding aryne adducts have been
transformed into extended perylene derivatives by deoxygenation and
aromatization with HCl/EtOH.