METHOD OF PREPARING 1,2-DIALKYL (PHENYL)CYCLO-BUT-1-ENES Russian patent published in 1998 - IPC

FIELD: pharmaceutical industry, more particularly synthesis of antiviral drugs, pesticides and low molecular weight bioregulators. SUBSTANCE: 1,2-dialkyl (phenyl) cyclobut-1-enes are prepared by reacting disubstituted acetylenes of general formula: R- ≡ -R, wherein R is Ph, н-C₃H₇ or н-C₄H₉ with triethyl aluminium in 10: (10- 12) molar ratio in the presence of dicyclopentadienyl zirconium chloride in amount of 2-5 mole % with respect to disubstituted acetylene in argon atmosphere at room temperature and under atmospheric pressure for 8 hours. Reaction mixture is then cooled to -5 C ether is added as solvent and catalyst consisting of palladium acetyl acelonate and triphenyl phosphine in 0.3:(0.3-0.9) molar ratio, and allyl chloride in triple molar excess with respect to AlEt₃. Reaction mixture is stirred at room temperature for 6-10 hours. On completion of reaction, reaction mixture is hydrolyzed with water to decompose catalyst system to give 1,2-dialkyl (phenyl)cyclobut-1- ones with total yield of 48-62%. EFFECT: more efficient preparation method. 1 tbl