15597.eh06.099-11211/2/0516:05Page106 ⊕ EQA 106 chapter 6 PROPERTES AND REACTIONS OF HALOALKANES:BIMOLECULAR NUCLEOPHILIC SUBSTTTUTON (37e)H;C-( o: )HC-Co: HO CHCHC form (afterc (e)CH,CH,CH,OH (d)CHCH,CH>I (e)CHCH.CH.CN () avery weak baseand thereforea or (g)CH,CH2CH2S(CHa)2*Br- (h)CH:*Br 40.(a)CH, >-CH.OCH.CH: (d)(CH)aCHCHaI (rather slowly) (e)CH;CH2CH2SCN (f)No reaction.F-is a very poor leaving group. (g)No reaction.OHis an even worse leaving group. (h)CHSCH, (i)No reaction.OCHCH3 is not a reasonable leaving group. 0 (D CHCH.OCCH he alide n that are red ictions (a)through (()nd ((CBrand are all good OSO,CH: 41.(R-CH.CHCH-CH,+NaN ()-CH,CHCHCH(37c) (37d) 39. (a) No reaction, although CH3CH2CH2OH would eventually form (after a few centuries). H2O is a very poor nucleophile. (b) No reaction. H2SO4 is a strong acid, a very weak base, and a very, very poor nucleophile! Its conjugate base, HSO4
, is a very weak nucleophile as well. (c) CH3CH2CH2OH (d) CH3CH2CH2I (e) CH3CH2CH2CN (f ) No reaction. As in (b), HCl is also a very weak base and therefore a dreadful excuse for a nucleophile. Being a strong acid, however, HCl can dissociate in appropriate solvents to release Cl
ions, which are moderately nucleophilic, so it would not be wrong to answer, “Slow formation of CH3CH2CH2Cl.” (g) CH3CH2CH2S(CH3)2 Br
(h) CH3CH2CH2NH3 Br
(i) No reaction. However, in the presence of heat or light, radical chlorination will occur, giving a mixture of products. (j) No (or very slow) reaction. F
is a rather poor nucleophile. (Note: F
is a much better nucleophile in aprotic solvents.) 40. (a) CH3CH2CH2CH2OH (b) CH3CH2Cl (c) (d) (CH3)2CHCH2I (rather slowly) (e) CH3CH2CH2SCN (f ) No reaction. F
is a very poor leaving group. (g) No reaction. OH
is an even worse leaving group. (h) CH3SCH3 (i) No reaction.
OCH2CH3 is not a reasonable leaving group. (j) The halide ions that are released in reactions (a) through (e), (h), and (j) (Cl
, Br
, and I
) are all good leaving groups. 41. (a) (R)-CH3CHCH2CH3 (S)-CH3CHCH2CH3 OSO2CH3 Na N3
N3 CH3OH CH3CH2OCCH3 O CH2OCH2CH3 H3C C O O Cl HO
H3C C O O Cl HO
106 • Chapter 6 PROPERTIES AND REACTIONS OF HALOALKANES: BIMOLECULAR NUCLEOPHILIC SUBSTITUTION 1559T_ch06_099-112 11/2/05 16:05 Page 106