2,3-diethylpentene-1 \text { 2,3-diethylpentene-1 } 2,3-diethylpentene-1
3,4-diethylpentene-4 \text { 3,4-diethylpentene-4 } 3,4-diethylpentene-4
3,3-diethylpentene-1 \text { 3,3-diethylpentene-1 } 3,3-diethylpentene-1
2-ethyl-methyl butane-1 \text { 2-ethyl-methyl butane-1 } 2-ethyl-methyl butane-1