1559r.ah08.132-14710/30/0511:59Page143 EQA Solutions to Problems143 (b)1.CH,CH2CH2CH2OH: 2.CH,CH2CH,CHO(Aldehyde): HO 3.CH.CH.CH.CH 4.CH.CH.CH.CH (Final product) (c)1.CH;CH2CHC C 3.CH;CH2CH2C- (Final product) D 43.The Wurtz reaction onstitutes the direct coupling of the nucleophilic carbon of an alkylsodium 44.A=BrMgCHaCHaCH.CH2MgBr (A"bis-Grignard"reagent) B=,(From addition of each end to aldehyde 45.(a)CHCHCI CH,OH (b)Same as(a),starting with ethane. (e)Same as(a),starting with propane.Not very good. (d)CHCH.CHCH,CHBrCH CH,CHOHCH (e)Same as (a).starting with butane.Not very good. (f)Same as(d).starting with butane.Much better. ((CHCH(CH.COH 46.Note:The halide (X)in all Grignard reagents may be Cl.Br.or I (a)From aldehydes.use CCCH.CHLC with (b)R=CH3,(c)R =CHaCH2,and (e)R=CH,CH2CH2.Finally. (d)CH.CHOCH,CHOHCH,and (either CH,CHOCH,CHOHCH,CH,r CH,CH.CHO CH,CH,CHOHCH,Solutions to Problems • 143 (b) 1. CH3CH2CH2CH2OH; 2. CH3CH2CH2CHO (Aldehyde); 3. 4. (c) 1. 3. 43. The Wurtz reaction constitutes the direct coupling of the nucleophilic carbon of an alkylsodium compound and the electrophilic carbon in a haloalkane. It is an unselective reaction. There is no way to control it to prevent coupling of two “like” alkyl groups while attempting to couple two different ones. In other words, the reaction between chloroethane and 1-chloropropane gives a statistical mixture of butane (from two ethyls), pentane (from an ethyl and a propyl), and hexane (from two propyls). 44. A  BrMgCH2CH2CH2CH2MgBr (A “bis-Grignard” reagent) B  CH3CHOHCH2CH2CH2CH2CHOHCH3 (From addition of each end to aldehyde) 45. (a) (b) Same as (a), starting with ethane. (c) Same as (a), starting with propane. Not very good. (d) (e) Same as (a), starting with butane. Not very good. (f ) Same as (d), starting with butane. Much better. (g) Beginning with alkanes, the only possible first step is halogenation. Functionalization of 1° carbons is difficult, too: Recall that radical halogenation favors 3° and 2° positions. 46. Note: The halide (X) in all Grignard reagents may be Cl, Br, or I. (a) From aldehydes, use for (a) R  H, (b) R  CH3, (c) R  CH3CH2, and (e) R  CH3CH2CH2. Alternatively, for all but the first one, use with (b) R  CH3, (c) R  CH3CH2, and (e) R  CH3CH2CH2. Finally, (d) and (f ) or CH3MgX or CH3Li CH3CH2CHO CH3CH2CHOHCH3 CH3CH2MgX or CH3CH2Li either CH3CHO CH3CHOHCH2CH3 CH3MgX or CH3Li CH3CHO CH3CHOHCH3 RMgX or RLi HCHO RCH2OH NaBH4 or LiAlH4 RCHO RCH2OH Br2, H2O (CH3)3CH (CH (CH3)3CBr 3)3COH Br2, H2O CH3CH2CH3 CH3CHBrCH3 CH3CHOHCH3 Cl2, hv HO
, H2O CH4 CH3Cl CH3OH CH3CH2CH2C OH (Final product) D CH3CH2CH2C O CH3CH2CH2CH HO CH (Final product) 3CH2CH2CH Li
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