question_answer 15)

Which of the following compounds would undergo aldol condensation, which the Cannizzaro reaction and which neither? Write the structures of the expected products of aldol condensation or Cannizzaro reaction. (i) Methanal                                       (ii) 2-methyl pentanal (iii) Benzaldeliyde                            (iv) Benzophenone (v) Cyclohexanone                          (vi) 1-phenyl propanone (vii) Phenyl acetaldehyde             (viii) Butan-1-ol (ix) 2,2-dimethyl butanal   (a) Compounds (aldehydes or ketones) having one or more  -H-atoms undergo aldol condensation. (b) Compounds (aldehydes) without -              H-atoms undergo Cannizzaro reaction. (c) Compounds (ketones) without--H-atoms will neither undergo aldol condensation nor Cannizzaro reaction. So write the structure of each compound to find the answer.  

Answer:

                (a) Compounds which undergo aldol condensation (having -hydrogen atom) are following: (i) 2-methyl pentanal (v) Cyclohexanone (vi) 1-phenyl propanone   (viii) Phenyl acetaldehyde (b) Compound which undergo Cannizzaro reaction: (Without -hydrogen atoms; only aldehydes) (i) Methanal (iii) Benzaldehyde (ix) 2,2-dimethyl butanal   (c) Compounds which undergo neither of the two reactions- Cannizzaro/Aldol: (iv) Benzophenone It is a ketone, so it does not undergo Canniyzaro's reaction. Without -hydrogen, it cannot participate in aldol condensation. (viii) Butan-1-ol It is an alcohol. So it cannot participate in any of the above 2 reactions.