Noël Hosten

A Novel Sensitive Colorimetric Assay for Visual Detection of Solid‐Phase Bound Amines

A new simple and efficient method for the detection of incomplete coupling reactions during solid-phase peptide synthesis is decribed. Using p-nitrophenyl ester 1 (NF31), free amino groups can be visually detected on the resin by direct coloring of the beads. A specific feature of the assay resides in the possibility of detection of sterically hindered primary amines.

A Short Intramolecular Diels−Alder Route to Himbacine Derivatives

The intramolecular cycloaddition of 5 yields the unsaturated lactones 17a, 17b, and 17c as three major isomeric adducts. These were further reduced to the corresponding derivatives 21a, 21b, and 21c, which are intermediates for the synthesis of (+)-himbacine and stereoisomers thereof. Precursor 5 was obtained in a short convergent way using Sonogashira and Stille coupling reactions as the main C−C bond construction reactions.