Construction of polycyclic ring systems fused to cyclobutane by cascade reactions of formyl α,β-unsaturated esters

Article abstract of DOI:10.1055/s-1995-4114

The intramolecular Michael-aldol reaction of methyl 7-formyloct-2-enoate (8) using iodotrimethylsilane (TMSI) and hexamethyldisilazane (TMS)₂NH produced the separable diastereoisomeric mixture of bicyclo[3.2.0]heptanes 9 and 10. Treatment of the α,β-unsaturated ester 19 possessing a formylcyclopropane function under the same reaction conditions caused cyclopropane ring opening-Michael aldol reaction to give the bicyclo[3.2.0]heptane 22. The filifolone derivative 31 was synthesized starting from 19 via 22.