We saw in Chapter 13 how stabilized carbanions - enols, enolated enamines - are key intermediates in biological isomerization reactions and in carbon-carbon bond-forming and bond-breaking events. In a...We saw in Chapter 13 how stabilized carbanions - enols, enolated enamines - are key intermediates in biological isomerization reactions and in carbon-carbon bond-forming and bond-breaking events. In a Michael addition, a nucleophile and a proton are 'added' to the two carbons of an alkene that is conjugated to a carbonyl. Finally, we will see how the coenzyme thiamine (vitamin B1) allows a carbonyl carbon to act as the nucleophile in a unique class of carbon-carbon bond-forming reaction.
