2-Butynedioic acid, dimethyl ester

Dimethyl acetylenedicarboxyl ate Acetylenedicarboxylic acid, dimethyl ester (8) 2-Butynedioic acid, dimethyl ester (9) (762-42-5)... 

Propargyl bromide 1-Propyne, 3-bromo- (8,9) (106-96-7) Dimethyl acetylenedicarboxylate Acetylenedicarboxylic acid, dimethyl ester (8) 2-Butynedioic acid, dimethyl ester (9) (762-42-5) l,2-Hexadien-5-yne (8,9) (33142-15-3)... 

Photolysis of n5 2,4-dimethylpentadien-l-yl manganese tricarbonyl [Mn(Tl5-2,4-Mc2C5H5)(CO)3] has been reported 59 to afford the THF adduct [Mn(T 5-2,4-Me2C5H5)(CO)2(THF)], which on reaction with butynedioic acid dimethyl ester and diphenylacetylene afforded respectively T 5-l,2-dimethoxycarbonyl-4,6-dimethylcyclohepta-2,4-dien-l-yl manganese tricarbonyl (39) and Ti5-4,6-dimethyl-l,2-diphenylcyclohepta-2,4-dien-l-yl manganese tricarbonyl (40) in formal [5 + 2] cycloaddition reactions. Propynoic acid methyl ester formed the 2 1 adduct T 5 2-i,3.dimethyl-6-methoxycarbonyl-6-( -2 -methoxycarbonylvinyl)-cyclohepta-2,4-dien-l-yl manganese dicarbonyl (41) which was characterised by X-ray diffraction. 

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