Diester-diyne

Novel polymerizable phosphatidylcholines were successfully synthesized by the research team of G. Just. To prepare a 32-membered macrocyclic diyne, the Eglinton modification of the Giaser coupiing was utilized. The diester-diyne starting material was slowly added to a refluxing solution containing 10 equivalents of cupric acetate in dry pyridine. The macrocycle was isolated in 54% yield after column chromatography. 

Parker, Raphael, and Wilkinson have investigated a synthetic approach to tropinone (124), which they call the acetylenic route (78). Reaction of hexa-1,5-diyne-l,6-dicarboxylate (145) with methylamine yields the pyrrolidine derivative (146), which by catalytic hydrogenation affords the diester 147 (79,50). 

In this method, diyne diester [1] was condensed with methylamine [2] to give the pyrrolidine diester [3]. Catalytic hydrogenation of [3] produced [4] which on Dieckmann cyclization (32), hydrolysis and decarboxylation gave tropinone [5]. 

Reductive cyclization of 1,6-diynes in the presence of triethylsilane and a catalyst prepared in situ from palladium(O) and acetic acid leads to dialkylidenecyclopentanes. Thus the diester 505 gave compound 506. ... 

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