Naming alkynes

Alkynes are hydrocarbons with carbon-carbon triple bonds as their functional group. Alkyne names generally have the -yne suffix, although some of their common names (acetylene, for example) do not conform to this rule. The triple bond is linear, so there is no possibility of geometric (cis-trans) isomerism in alkynes. 

The relative stabilities of vinyl cations also can be given by the gas-phase basicity AAG(cc)h+ of alkynes, namely as the standard free energy change for the protonation reaction (28). 

In this section we report our experimental findings relatively to three different reactions of CN radicals with simple alkynes, namely acetylene, methyl-acetylene and dimethyl-acetylene. We have selected these reactive systems for different reasons the reactions with C2H2 is the prototype for the class of reactions CN +- alkynes/polyynes, thus is expected to reveal key concepts for reactions with the higher members of the same series the reactions with methylacetylene and dimethylacetylene were selected to observe the effect of the H substitution with one or two alkyl groups. In all cases, the experimental results are discussed in the light of the ab initio electronic structure calculations for the stationary points of the relevant potential energy surfaces. 

Another application of the concept of transition metal-catalyzed cross-coupling is coupling of aryl or alkenyl halides with alkynes, named Sonogashira coupling (Eq. 1.4) [22]. 

The alkynes contain triple bonds and possess a linear geometry of the two carbons and the two attached groups. Alkyne names end in -yne. 

A different route to the intermediary Michael acceptor was used in the synthesis of 3-(hetero)aryl-lH-pyrazoles 28. In contrast to previously described approaches, the terminal alkyne, namely propynal diethylacetal (5d), was utilized to introduce the carbonyl group. Propynal diethylacetal (5d) acts as a synthetic equivalent of propargyl aldehyde and, thus, Sonoga-shira cross-coupling of (hetero)aryl iodides 6 and propynal diethylacetal (5d) and subsequent acetal cleavage and concomitant cyclocondensation in the presence of para-toluenesulfonic acid and hydrazine hydrochloride (20a) furnishes the title compounds (Scheme 15) (201 lMOM(l6)9340). 

Number the carbon chain of the parent compound starting with the end nearer to the double or triple bond. Use the smaller of the two numbers on the double- or triple-bonded carbon atoms to indicate the position of the double or triple bond. Place this number in front of the alkene or alkyne name 2-butene means that the carbon-carbon double bond is between C-2 and C-3. 

Give the location and name of each substituent (alphabetical order) as a prefix to the alkene or alkyne name. 

Problem 7.6 One of the intermediate compounds in the synthesis of the spruce budworm sex pheromone is (.E)- 1-tetradecen-l-ol. How can this compound be produced from a substituted alkyne Name the alkyne. 

The carboxylic acid group has a higher priority than double or triple bonds. To name a carboxylic acid that contains a double or triple bond, replace the final -e of the name of the parent alkene or alkyne name with the suffix -ok acid. Indicate the position of the multiple bond with a prefix. 

STEP0 Number the carbon chain starting from the end nearer the triple bond. Place the number of the first carbon in the triple bond in front of the alkyne name. 

The lUPAC names of alkenes end with ene, while alkyne names end with yne. The main chain is numbered from the end nearer the double or triple bond. 

---