216 ALKYNES The desired intermediate, 1-butyne, is available by halogenation followed by dehydrohalo- genation of 1-butene I NaNH, NH, CH,CHLCH=CH, Br2 CHCH CHCH,Br 2HO CH2CHC≡CH 1-Butene Reaction of the anion of 1-butyne with ethyl bromide completes the synthesis CH2CH2C≡CH CH2CH2C≡ Cuzo CHCHC=CCh, CH 3-Hexyne (b) Dehydrohalogenation of 1, l-dichlorobutane yields 1-butyne. The synthesis is completed as in part(a). 1. NaNH2, NHs CH,CH,CH,CHCI 2H,o →CH3CH2C≡CH LI-Dichlorobutane NaNH, (c)HC≡CH HC≡C:Na+ CH, CHB, HC≡CCH2CH3 1-Butyne is converted to 3-hexyne as in part(a) 9.25 A single dehydrobromination step occurs in the conversion of 1, 2-dibromodecane to CioHjgBr Bromine may be lost from C-l to give 2-bromo-l-decene BrCH, CH(CH,)CH3 H,C=C(CH2),CH Br L2-Dibromodecane Loss of bromine from C-2 gives(E)-and(z)-l-bromo-1-decene (CH,_CH (CH2),CH3 BrCH, CH(CH,),CHa- =C B H 1. 2-Dibromodecane (Erl-Bromo-I-decene 9.26(a) CH, CH, CH,CH,CECH 2H2 CHa CH, CH,CH,,CH3 l-Hexyne (b) CH CH, CH, CH,C=CH H Lindlar p CH CH, CH, CH, CH=CH, 1-Hexene (c)CH3CH2CH2CH2C≡CH CH,CHCH,CH=CH 1-Hexyne 1-Hexene Back Forward Main Menu TOC Study Guide Toc Student OLC MHHE WebsiteThe desired intermediate, 1-butyne, is available by halogenation followed by dehydrohalo￾genation of 1-butene. Reaction of the anion of 1-butyne with ethyl bromide completes the synthesis. (b) Dehydrohalogenation of 1,1-dichlorobutane yields 1-butyne. The synthesis is completed as in part (a). (c) 1-Butyne is converted to 3-hexyne as in part (a). 9.25 A single dehydrobromination step occurs in the conversion of 1,2-dibromodecane to C10H19Br. Bromine may be lost from C-1 to give 2-bromo-1-decene. Loss of bromine from C-2 gives (E)- and (Z)-1-bromo-1-decene. 9.26 (a) (b) (c) CH3CH2CH2CH2C CH NH3 Li CH3CH2CH2CH2CH CH2 1-Hexyne 1-Hexene CH3CH2CH2CH2C 1-Hexyne CH H 2 Lindlar Pd CH3CH2CH2CH2CH 1-Hexene CH2 CH3CH2CH2CH2C 1-Hexyne CH 2H 2 Pt CH3CH2CH2CH2CH2CH3 Hexane Br BrCH2CH(CH2)7CH3 1,2-Dibromodecane KOH ethanol–water C C Br H H (CH2)7CH3 (E)-1-Bromo-1-decene C C H Br H (CH2)7CH3 (Z)-1-Bromo-1-decene H2C 2-Bromo-1-decene Br Br BrCH2CH(CH2)7CH3 1,2-Dibromodecane KOH ethanol–water C(CH2)7CH3 HC CH HC Acetylene NaNH2 NH3 C Na CH3CH2Br HC 1-Butyne CCH2CH3 1. NaNH2, NH3 2. H2O CH3CH2C CH 1-Butyne CH3CH2CH2CHCl2 1,1-Dichlorobutane CH3CH2C CH CH3CH2C 1-Butyne NaNH2 NH3 C Na CH3CH2Br 3-Hexyne CH3CH2C CCH2CH3 Br2 1. NaNH2, NH3 CH3CH2CHCH2Br 2. H2O CH3CH2C CH 1-Butyne Br CH3CH2CH CH2 1-Butene 216 ALKYNES Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website