Alkinyl esters

Employing alkinyl esters bearing an aldehyde group with different chain length, an intramolecular reaction occurs giving five- to eight-membered cyclic systems. 

Alternatively polymer-bound sodium selenide 6 served as the starting point for an acylat-ing protocol (Scheme 3) [12]. Transformation into selenol ester 9 afforded an active polymer-bound intermediate which was cleaved in the presence of an alkinylcopper species to generate a,/ -alkinyl ketones 10 while the copper selenide can be reacylated using acyl chlorides. 

Butyl-1,2,3-trihydroxy- VI/lc, 1062 Bernstein-4-aldehyd-l -Saure 3,3-Di-methyl-2-ethenyliden- -ethyl-ester E3, 575 (Aik —alkinyl acetai-Umlager.)... 

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