Dienophile as an Additional Component

Amino ester took part in this reaction effectively, leading to the functionalized pyrrolopyridine as a separable mixture of two diastereomers. The conditions were sufficiently mild so that no epimerization was observed. 

3 Substrate Design Approach in the Development of Novel MCRs 595 O 

The above reaction has been successfully appHed to a three-step synthesis of tetracychc compounds, akin to the lennoxamine- and nuevamine-type natural products [35]. 

The power of the substrate design approach is therefore once again demonstrated from the above two examples. By simply changing the nature of the dienophile (double bond vs triple bond), we were able to synthesize completely different heterocycles starting from the same oxazole, which was in turn synthesized in situ by a three-component reaction. 

By combing the three-component synthesis of oxazole with the above two bimolecular domino processes, a five-component reaction was subsequently developed [37]. The optimized conditions consisted of performing the reaction in toluene in the presence of a catalytic amount of camphorsulfonic acid (CSA, O.lequiv). 

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