Question

(a) Using S-2-chlorobutane as an example, compare and contrast Syl and SN2 reactions. Things you may wish to consider are: i. stereochemistry ii. solvent iii. leaving group iv. strength of nucleophile

Answer 1

S-2-chlorobutane 대로 내3 S-2-Chlorobutane j) Stereochemistry SN2 reaction broceed via inversion of configuration since nucleo attack from back side and invewion occur. In this Transition state formed. CH₂ U13 CH₂CH3 -OH cu Hec' ue Hora S-2-chlorobutane R-2-butanol Cinversion occur) SNI : In Snl mechanism reaction proceed via Carbocation intermediate since Carbo Cation is planar so attack can occur above the plane as well as below the plane so racemic mixture stormed. 010 но я CH₂ CH3 CH 2012 r Het ho Arbocahim Abutanol $-2-butanol R-2-buhanel Solvent SN2 Mechaniom arour by polgy apronic Solvent. Since in boley brohie solvent , nucleophile can get solrated and do not attack effectively Spi mechanism favous by polar prolic solvent. since in SNI mechanism Carbocation formed and stabilised by protic solvent.

1) leaving group: For SN2 Relative reactivities of alkyl heleide in an SN2 renction RI>RBOZ RUDRF sina relative leaving abilities of the hallide ion I^> B7-76->F- For Sna Relative reactivites y altye hallide in an SNq reaction R27 RBY > RURF so for both SNI & SN2 leaving group is same it does not affect rate of reaction. strength of nucleophile An SN 2 reaction is favoured by a high concentration of a good nucleophile (Ford Ex: 04, CH3 CH20, C30) An sNI reaction is favoured ty a low concentration of a nucleophile or by poor nucleophile (for ex H2O, C1200) CHq CH3 so Chacha 23 -ou - chacha 4 SN2 S 5 H Chachs 12 CH3 Chacha J- H₂O به وه یا 1 ماه