[2-ARYLFURAN-2,3-DIONES TO TRIMETHYLSILYLOXYETHYLENES(2]PHOTOCYCLOADDITION REACTION OF 5)

The photocycloaddition reaction of 5-phenylfuran-2,3-dione (1a) to 2-t rimethylsilyloxybutadiene proceeded in a [2s+2s] manner with high regi o- and stereo-selectivities to give a 2-oxabicyclo[3.2.0]heptane-3,4-d ione 2 with 7-endo-OTMS-7-exo-vinyl stereochemistry, 5-Arylfuran-2,3-d iones (1a-e) on similar photocycloaddition with 1-phenyl-1-trimethylsi lyloxyethylene gave the corresponding 7-aryl derivatives 3a-e with the same regio- and stereo-chemistries in good yields, This stereochemica l result of O-endo selectivity is consistent with the prediction obtai ned from the stereo-selection rule proposed for the enone-olefin photo cycloaddition reaction. The reaction provides an efficient method for the synthesis of poly-functionalized cyclobutane derivatives.