Oct-3-yne

However, attempts to couple (/V-acety l)-4-iodopyrazole 36 under the same conditions with phenylacetylene, p-methoxyphenylacetylene, and oct-1 -yne, once again, were unsuccessful, instead, reductive deiodination to give 5-(/V-acetylamino)-3-methyl-l-ethylpyrazole and homo-coupling of alk-l-yne occurred (Scheme 49). The isomeric 3-(/V-acetylamino)pyrazole 37 was somewhat less inclined to deiodination. 

Fig. 12. A traditional example of an acyclic carbon compounds and its IUPAC name 3(2-propynyl),5-methenyl-oct-1,2-diene,6-yne...

Figure 12-8 compares the IR spectra of oct-l-yne and oct-4-yne. In addition to the alkane absorptions, the oct-l-yne spectrum shows sharp peaks at 3313 and 2119 cm-1. The absorption at 3313 cm-1 results from stretching of the stiff = C—H bond formed by the sp hybrid alkyne carbon. The 2119 cm-1 absorption results from stretching of the C=C triple bond. 

The spectrum of oct-4-yne is not very helpful. Since there is no acetylenic hydrogen, there is no =C—H stretching absorption around 3300 cm-1. There is no visible C=C stretching absorption around 2100 to 2200 cm-1 either, because the disubsti-tuted triple bond has a very small dipole moment. This spectrum fails to alert us to the presence of a triple bond. 

It was found that by applying the same reaction conditions as for the intermolecular reaction, they were able to obtain moderate yields of bicyclic products (Scheme 2). Starting from hept-l-en-6-yne, they were able to generate the 5,5-ringed bicyclo[3.3.0]oct-l-en-3-one (4). Increasing the carbon tether by one carbon unit and using oct-1-en-7-yne led to the generation... 

Benzocyclopropene (88) and naphtho[h]cyclopropene react with various alkenic substrates to give cy-cloaddidon piquets in the presence of silver ion. Reaction of (88 equation 39) with butadiene assisted by 1 mol % of AgBp4 in benzene (0 C, 30 min) gives (89) and (90). Dimethylallene (91 equation 40) and oct-4-yne (95 equation 41) also react readily with (88) in the presence of silver ion to give the corresponding cycloaddition products (92), (93) and (96), together with acyclic products (94) and (97). 

An alkynylcyclopropane was also formed on heating a 10-selena-l 1,12-diazatricyclo[6.3.0.0 ]-dodeca-l(9),ll-diene under reduced pressure to give bicyclo[6.1.0]oct-2-yne in 21% yield. When the thermolysis was carried out in the presence of 2,3,4,5-tetraphenylcyclopenta-2,4-dienone, the alkyne underwent a Diels-Alder reaction subsequent decarbonylation gave 10,11,12,13-tetraphenyltricyclo[6.4.0.0 ]trideca-l (9),10,12-triene. ... 

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