Diastereotopos-differentiating allylic alkylation as a key step in the synthesis of gamma-glutamyl boletine

Asymmetric total syntheses of sarglamides A, C, D, E, and F

Sarglamides A-E were identified as a structurally new class of alkaloids with potential application for inflammation-associated diseases. Reported is the first asymmetric total synthesis of sarglamides A, C, D, E, and F within 7 steps, featuring an intermolecular Diels-Alder cycloaddition of (S)-phellandrene and 1,4-benzoquinone and intramolecular (aza-)Michael addition to construct the tetracyclic core of sarglamides. Importantly, our work demonstrated that the hypothetic Diels-Alder reaction of α-phellandrene with dienophile toussaintine C (or analogues) originally proposed as a biosynthetic pathway was not viable under non-enzymatic conditions. Additionally, we discovered novel and efficient double cyclization (cycloetherification and oxa-Michael cyclization) to construct the core framework of sarglamides E and D. Our concise synthetic strategy might allow rapid access to a library of sarglamide analogues for further evaluation of their bioactivity and mode of action.

Non-stabilized enolates – versatile nucleophiles in transition metal-catalysed allylic alkylations

This review covers new developments in the transition metal-catalyzed allylic alkylations of non-stabilized enolates, preferentially generated from ketone, esters or amides.

Synthetic studies towards bottromycin

Thio-Ugi reactions are described as an excellent synthetic tool for the synthesis of sterically highly hindered endothiopeptides. S-Methylation and subsequent amidine formation can be carried out in an inter- as well as in an intramolecular fashion. The intramolecular approach allows the synthesis of the bottromycin ring system in a straightforward manner.