Question

3.8. Provide a mechanistic interpretation of the following reactions and observations. a. Show the mechanism for inversion of a hydroxyl site under the Mitsunobu conditions, as illustrated by the reaction of cholesterol. H₃ C C₂H17 Hzc | нс сH17 1) PhaP, HCOH 2) C,H,O,CN=NCO,CH HCO Hgc

Answer 1

1st step is triphenylphosphine react with DEAD to form phosphonium intermediate the alcohol attacks on these intermediate makes alcohol good leaving group then attack formic acid ion on backside gives inverted product.

(6H11 (6HIT oph P,HC00H HC HCguh HsOz CNENCOGM5 Mechantm- haP N-HLOEY -OEH to PPh3 H-H pha Ceti7 CCHIT Ophx