Pyrrole, acylation reaction with electrophilic alkenes

The trouble is that pyrrole will not do this reaction as it is so good at electrophilic substitution. What happens instead is that pyrrole acts as a nucleophile and attacks the electron-deficient alkene. The answer is to make pyrrole less nucleophil ic by acylating the nitrogen atom with the famous Boc protecting group (Chapter 24). We will see in the next section how this may be done. A good Diels-Alder reaction then occurs with a alkynyl sulfone. 

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