《有机化学》课程PPT教学课件（Organic Chemistry with Biological Applications, 3th Edition, John McMurry, 2016）Chapter 07 Alkenes and Alkynes

Naming Alkenes and Alkynes Step 3-Write the full name using suffix -ene in place of- ane If more than one double bond indicate position and use suffixes -diene,-triene,and so on CH3 CH3CH2CH2CH-CHCH3 CH3CHCH=CHCH2CH3 65 4321 12345-6 Hex-2-ene 2-Methylhex-3-ene CH3CH2 H 2C=C1 CH3 CH3CH2CH2 H 5 4 3 H29=99H=gH2 2-Ethylpent-1-ene 2-Methylbuta-1,3-diene

▪ Step 3 - Write the full name using suffix -ene in place of - ane ▪ If more than one double bond indicate position and use suffixes -diene, -triene, and so on Naming Alkenes and Alkynes

Naming Alkenes and Alkynes Older naming system still in use which places the locant,or number locating the position of the double bond,at the beginning of the name CH3 CH3 CH2CH2CH3 CH3CH2CHCH-CHCHCH3 H2C=CHCHCH-CHCH3 7654 321 123456 Newer naming system: 2,5-Dimethylhept-3-ene 3-Propylhexa-1,4-diene (Older naming system: 2,5-Dimethyl-3-heptene 3-Propyl-1,4-hexadiene)

▪ Older naming system still in use which places the locant, or number locating the position of the double bond, at the beginning of the name Naming Alkenes and Alkynes

Naming Alkenes and Alkynes Cycloalkenes Number cycloalkene so double bond is between C1 and C2 and first substituent has lowest number possible CH3 CH3 CH3 1-Methylcyclohexene New name:Cyclohexa-1,4-diene 1,5-Dimethylcyclopentene (Old name:1,4-Cyclohexadiene) ngnge Leaming All Pighes Peserved

▪ Cycloalkenes ▪ Number cycloalkene so double bond is between C1 and C2 and first substituent has lowest number possible Naming Alkenes and Alkynes

Naming Alkenes and Alkynes Common names that are often used and are recognized by IUPAC: H2C专 H2C=CH之 H2C=CH-CH2专 A methylene group A vinyl group An allyl group TABLE71 Common Names of Some Alkenes Compound Systematic name Common name H2C-CH2 Ethene Ethylene CH3CH-CH2 Propene Propylene CH3 2-Methylpropene Isobutylene CH3C=CH2 CH3 2-Methylbuta-1,3-diene Isoprene H2C=C-CH=CH2

Common names that are often used and are recognized by IUPAC: Naming Alkenes and Alkynes

Naming Alkenes and Alkynes Alkynes Named just like alkenes using suffix-yne Number main chain so triple bond receives as low a number as possible CH3 CH3CH2CHCH2C=CCH2CH3 Begin numbering at the end 87654321 nearer the triple bond. New name:6-Methyloct-3-yne (Old name:6-Methyl-3-octyne)

Alkynes ▪ Named just like alkenes using suffix -yne ▪ Number main chain so triple bond receives as low a number as possible Naming Alkenes and Alkynes