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Synthesis and reactions of rhenium enyne, and vinylalkenylidene complexes

1994; Elsevier BV; Volume: 472; Issue: 1-2 Linguagem: Inglês

10.1016/0022-328x(94)80205-x

1872-8561

Charles P. Casey, Yunkyoung Ha, Douglas R. Powell,

Catalytic Alkyne Reactions

Abstract Reaction of Cp★Re(CO) 2 (THF) with HCCC(CH 3 )CH 2 produced the conjugated enyne complex Cp★(CO) 2 Re[η 2 -HCCC(CH 3 CH 2 ] ( 1 ). Attempted preparation of an η 3 -propargyl complex by protonation of 1 with HBF 4 failed. Thermolysis of 1 led to the corresponding alkenylidene complex Cp★(CO) 2 ReCCHC(CH 3 )CH 2 ( 2 ), which reacted with HBF 4 to give the cationic alkylidyne complex [Cp★(CO) 2 ReCCHC(CH 3 ) 2 ][BF 4 ] ( 3 ). Nucleophiles including NaCH(CO 2 C 2 H 5 ) 2 , PMe 3 , and NaBH 4 attack regioselectively at the γ-carbon of the alkylidyne ligand of 3 . Both the conjugated enyne complex 1 and vinylalkenylidene complex 2 underwent reaction with dimethyl acetylenedicarboxylate (DMAD), eventually producing dimethyl 4-methylphthalate ( 9 ).