Glaser—Hay coupling

With its two different protective groups, derivative 109 could be selectively depro-tected to the free acetylene 110 that, on Glaser-Hay coupling, furnished the highly unsaturated dimer 111 (72%), probably as a mixture of two diastereomers. Although comparable approaches to prepare derivatives of the parent hydrocarbon 10 and 11 (Scheme 5.1) have so far failed, with the protected 1,1-diethynylallene 112 a first representative of the cross-conjugated diethynylallene 9 could be synthesized [40],... 

Table 1. Oligomerization and polymerization of compound 1 by Glaser-Hay coupling. Catalyst formation CuCI, TMEDA, and 02 in 1,2-dichlorobenzene [5, 12]. The reaction was performed in the presence of molecular sieves (4 A). If PhC=CH was available immediately at beginning ofthe coupling process (procedure C) an equal amount was added again 1 h before the end of the reaction. (tr is the total reaction time and tadd is the time until addition of the end-capping reagent.)...

Metal coordination also enables organic ligands to be used as templates. Sanders and co-workers have synthesized cyclic porphyrin oligomers using Glaser-Hay coupling [16,40]. This reaction oxidatively combines two terminal acetylenes to give a 1,3-buta-diyne link. The syntheses of cyclic porphyrin dimer 38 and trimer 39 were effectively templated by 4,4 -bipyridine 37 and tripyridyltriazine 22, respectively (Scheme 1-10). 

As described in Section III.A.2, Sanders and McCallien assembled four Zn(II) dioxoporphyrins bearing acetylenic groups on the tetrakis(4-pyridyl) porphyrin template 61. They subsequently submitted the complex to the Glaser-Hay coupling reaction which produced the cyclic tetramer in 70% yield. Without a template, the same reaction was not so selective it afforded the tetramer and trimer species in 40%... 

Anderson et al. synthesized the soluble conjugated porphyrin polymer of 5,10,15,20-diethylnyl zinc porphyrin (DEtyP)n using Glaser-Hay coupling (Figure 34). The real and imaginary components of / (—0,0, to) of the.se polymers were calculated from the electroabsorption spectra. The / (-m 0,0, (o) on the order of 7.3 x 10 esu was obtained at the peak resonance due to resonance enhancement. 

Sometimes known as the Glaser-Hay coupling, it is the oxidative homo-coupling of terminal alkynes using copper catalyst in the presence of oxygen. 

Figure 2. Glaser-Hay coupling of 3 to give cyclic porphyrin oligomers.

Figure 10. Synthesis of linear octamer SiiZngll by Glaser-Hay coupling of a mixture of linear tetramers (R = H, SiMes) using 11 as scavenging template.

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