Cyclotrimerization of acetylenes catalyzed by (η5-cyclopentadienyl)rhodium complexes
作者:Khalid Abdulla、Brian L. Booth、Catherine Stacey
DOI:10.1016/0022-328x(85)80250-3
日期:1985.9
comparative rates of cyclotrimerization of dimethylacetylenedicarboxylate (DMAD) and hex-3-yne have been studied with the catalysts [η5-C5R5)Rh(COD)] (R = H, Me, Cl; COD = cycloocta-1,5-diene), [(η5-C5R5)Rh(CO)2] (R = H, Me), [(η5-C5Me5RhL2] (L = C2H4, PF3) and [(η5-C5H4PPh3)Rh(CO)2]+ PF6− under pseudo-first-order conditions. In these reactions, which all obey the rate law, rate = kobs [acetylene], the rate
丁炔二酸二甲酯(DMAD)和环化三聚的比较率己-3-炔已经研究了与催化剂[η 5 -C 5 - [R 5)的Rh(COD)](R = H,Me中的氯; COD =环辛1 ,5-二烯),[(η 5 -C 5 - [R 5)的Rh(CO)2 ](R = H,Me)时,[(η 5 -C 5我5 RHL 2 ](L = C 2 H ^ 4, PF 3)和[(η 5 -C 5 H ^ 4 PPH 3)的Rh(CO)2 ] + PF 6 -在伪一阶条件下。在这些均符合速率定律的反应中,速率= k obs [乙炔],随着环戊二烯基配体的π-受体强度增加,DMAD的环三聚速率降低,并且在hex-3-反应中这种趋势被逆转恩。环三聚的速率也出现与配位体L的性质改变(其中L = C 2 H ^ 4,CO,PF 3,12 COD)暗示使得L遗体结合于铑原子在整个催化循环。初步研究表明,在某些情况下,选择性共低聚发