Function Posted January 3, 2015 Share Posted January 3, 2015 Hi everyone Asked is to give all possible elimination products after elimination of 3-methyl-butan-2-ol in a sulfuric-acidic/water environment. The answer would be: (mostly) 2-methyl-but-2-ene (a bit) 3-methyl-but-1-ene Why can't 2-methyl-but-1-ene be formed? It's not like the second possibility is conform Zaitsev's rule so... Why not 2-methyl-but-1-ene? Thanks! F. Link to comment Share on other sites More sharing options...
brake4country Posted April 10, 2015 Share Posted April 10, 2015 Hello there, Actually, your 2-methyl-but-1-ene is labeled incorrectly. The double bond gets priority, so it should be 3-methyl-1-butene. To answer your question, since this is an elimination reaction, we have to consider beta hydrogens. The major product (2-methyl-but-2-ene) would be formed moreso over the 3-methyl-1-butene. This is because if the reaction proceeded as a carbocation, the tertiary carbon is more stable, hence creating a major product of 2-methyl-but-2-ene. The minor product is only a small yield because upon elimination of a beta hydrogen, a secondary carbocation would be formed (the relative reactivity of carbocations are 3>2>1. It's not that the minor product is not formed at all, but it would be in a small amount compared to your major product. Link to comment Share on other sites More sharing options...
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