enter image description here

Which compounds are not useful for preparation of grignard reagents?

a) 4-chlorobut-1-yne
b) 2-chloroethan-1-amine
c) 1-bromobutan-2-ol
d) 4-bromocyclohexan-1-ol


closed as off-topic by Gaurang Tandon, Tyberius, aventurin, Mithoron, Todd Minehardt Jun 21 '18 at 16:37

This question appears to be off-topic. The users who voted to close gave this specific reason:

If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ What are your thoughts on this? $\endgroup$ – Waylander Jun 20 '18 at 14:43
  • 2
    $\begingroup$ Is this a trick question? $\endgroup$ – ringo Jun 20 '18 at 14:49

Seems to me that there are solid reasons why NONE of the materials will form Grignards unless they are modified.

1 - The alkyne proton (pKa ~25) will quench any Grignard formed to give the Mg salt

2 - The free base is already unstable in solution wrt aziridine formation/polymerisation; any added base promotes this. Any Grignard formed will also be quenched by the NH2 protons.

3- The -OH proton will quench any Grignard forming the alkoxide which is liable to form the epoxide.

4- Similarly the -OH proton will quench any Grignard forming the alkoxide which can then form the tetrahydrofuran


Not the answer you're looking for? Browse other questions tagged or ask your own question.