Chirality in Ugi synthesis

Experiment 14 (you should have linked to the experiment not the blog main page) is the Ugi synthesis and cyclization to a diketopiperazine using phenylacetaldehyde, 5-methylfurfurylamine, N-(tert)butoxycarboyl L-methionine, and benzylisocyanide.

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2-[(tert-butoxycarbonyl)amino]-4-(methylthio)butanoic acid

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Benzyl isocyanide

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Each of these reactants is a chiral molecule because their mirror images are nonsuperimposible.
this is wrong - talk to me at a workshop before the exam to make sure you understand how to tell chirality
However, only one of the reactants, 2-[(tert-butoxycarbonyl)amino]-4-(methylthio)butanoic acid contains a chiral center. Having a chiral center is not the only factor of a chiral compound, for example the other reactants could have axial or planar chirality.

The chiral center in 2-[(tert-butoxycarbonyl)amino]-4-(methylthio)butanoic acid is the 2nd carbon, which is bonded to HOCO, H, tert-butoxycaronylamino, and CH2CH2SCH3. Because the compound has only one chiral center, it is chiral.

The product of the reaction, the diketopiperazine, contains 2 chiral centers. A compound with more than one chiral center may or may not be chiral. Also, because the molecule has 2 chiral centers, it should have 4 stereoisomers, following the 2^n rule. The stereoisomers could be enantiomers or diastereomers, which are not mirror images.

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