1559T_ch07_113-13111/2/0516:06Page119 ⊕ EQA Solutions to Problems.119 ecan attach to either face of the planar cationic carbon.reactions yielding the two Br CHa By reattachment of Brto the opposite side of cationic carbon.(Reversal of the dissociation step.) 25.Two products: and From attachment of nucleophile to either face of the planar cation olarity and accelerate S reactions (see Problem 45.however).The ()(b)e ooadprodtstee (allye ⊕ (d)This solvent should reduce polarity and slow down all the solvolyses. Tertiary） Secondary Primary 28.(a)(CH3)CCICH-CH3>(CH3)2CHCHCICH>(CH)2CHCHCH2CI (3>2>1) 0 (b)RCI>ROCCHs>ROH (Order of leaving group ability) 29.(a)A secondary system withan excellent leaving group and a poor nucleophile reaction (CHCHCose0,cE,一os0,C乐，+(cH,dqHa H (CH)CHOCH.CH,-+(CHCHOCH-CH The nucleophile can attach to either face of the planar cationic carbon, reactions yielding the two products shown. (b) By reattachment of Br
to the opposite side of cationic carbon. (Reversal of the dissociation step.) 25. Two products: From attachment of nucleophile to either face of the planar cation. 26. (a) H2O will speed up all of the reactions except for 22(d), because it is more polar than any of the other solvolysis solvents. It will also compete for the carbocations, forming alcohols as products. (b) Ionic salts strongly increase polarity and accelerate SN1 reactions (see Problem 45, however). The main products will be iodoalkanes. (c) Same as (b); azide ion is a strong nucleophile and products will be azidoalkanes (alkyl azides, RON3). (d) This solvent should reduce polarity and slow down all the solvolyses. 27. 28. (a) (CH3)2CClCH2CH3 (CH3)2CHCHClCH3 (CH3)2CHCH2CH2Cl (3 2 1) (b) (Order of leaving group ability) (c) 29. (a) A secondary system with an excellent leaving group and a poor nucleophile F SN1 reaction.
OSO2CF3 (CH3)2CHOCH2CH3 CH3CH2 (CH3)2CH (CH3)2CHOCH2CH3 (CH3)2CH OSO2CF3 OH H H CH3 Cl Br Cl RCl ROCCH3 ROH O H CH2 (Primary) H CH3 (Secondary) CH3 (Tertiary) C6H5 CH3 C6H5 H CH3 CH3CH2O C6H5 C6H5 CH3 H CH3 OCH2CH3 and CH3 CH3 Br H Solutions to Problems • 119 1559T_ch07_113-131 11/2/05 16:06 Page 119