2,2'-Bifurylidene-5,5'-diones, Coumarins, 3a,7a-Dihydro-1H-inden-1-ones, and 5H-Furopyran-5-ones from Propyne and Carbon Monoxide

Article abstract of DOI:10.1002/hlca.19890720423

The -catalyzed reaction between propyne and CO in acetone at 110 deg C and 170 bar was reinvestigated.There are five major products: (E)-3,4'-dimethyl-2,2'-bifurylidene-5,5'-dione (4), 3,5,8-trimethylcoumarin (8), 3a,7a-dihydro-2,4,7,7a-tetramethyl-1H-inden-1-one (9), 2,6-dimethyl-5H-furo<3,2-b>pyran-5-one (11), and 2,7-dimethyl-5H-furo<3,2-b>pyran-5-one (12); of these, only one, 4, had previously been recognized.In parallel experiments were obtained 2,6-dipentyl-5H-furo<3,2-b>pyran-5-one (13), 2,7-dipentyl-5H-furo<3,2-b>pyran-5-one (14), 3a,7a-dihydro-2,4,7,7a-tetrapentyl-1H-inden-1-one (15), and 3a,7a-dihydro-2,4,6,7a-tetrapentyl-1H-inden-1-one (16) from hept-1-yne, and two further types of products from two atypical 1-alkynes: 3,6,9-tri(tert-butyl)-1-oxaspiro<4.4>nona-3,6,8-trien-2-one (20) from (tert-butyl)acetylene and the exo-dimer 21 of 2,5-bis(trimethylsilyl)cyclopenta-2,4-dien-1-one (22) from (trimethylsilyl)acetylene.Compounds 11, 12, and 20 were identified by X-ray analysis.