Copper(I)/succinic acid cooperatively catalyzed one-pot synthesis of organoselenium-propargylamines via A3-coupling

ABSTRACT

Selenium propargylamines were synthesized via an A(3)-coupling approach using piperidine, p-methoxybenzaldehyde, and trimethylsilyl selenium-acetylene, catalyzed by copper(i) chloride and succinic acid as an additive, in good to excellent yields. This method is advantageous in that desilylation of the trimethylsilyl selenium-acetylene occurs in situ. The reaction time was monitored by FTIR studies and a probable mechanism is described. Scale-up was also performed in satisfactory yield. These selenium propargylamines could be hydrohalogenated to synthesize halovinyl selenides. The stereochemistry was determined by treatment with n-butyllithium and the coupling constant (J) values in H-1 NMR spectra. The vinyl selenides were employed in Sonogashira cross-coupling reactions to produce the corresponding enynes, with yields ranging from moderate to good.