SummaryComplex amino acids with an α-acyloxycarbonyl functionality in the side chain are easily available through epoxide opening by chelated enolates and subsequent oxidation/Passerini reaction. This protocol works with both, aldehyde and ketone intermediates, as long as the ketones are activated by electron-withdrawing groups. In principle Ugi reactions are also possible, allowing the generation of diamino acid derivatives.

Quantum chemical methods are used to study the solvent effects on the spectra of indole and a series of methyl‐substituted indoles. We focus on the low‐lying La and Lb states and study their interplay. We find that the solvent mainly affects emission from the La state, by stabilizing its energy in its excited‐state geometry. The stabilization of the La state increases with increasing solvent polarity, which accounts for the large fluorescence shift observed in indoles and leads to an inversion in the nature of the lowest emitting state, from Lb in vacuum to La in water. To the best of our knowledge, this is the first theoretical evidence for level inversion done for a series of indoles. The underlying mechanism of level inversion is analyzed in detail. The usual interpretation of level inversion in terms of their static dipole moment is criticized and an improved predictive measurement is suggested.

A l l y l a t i o n o f A m i n o A c i d s a n d P e p t i d e s w i t h V i n y l e p o x i d e s

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