A Bromoarene Based Approach to Phenylalanine Analogues Hic and Nic

Abstract

A Heck reaction system incorporating Ph 4 PCl and using bromoarenes as substrates has enabled the syntheses of the conformationally constrained phenylalanine analogues Hic and Nic to be dramatically shortened thus facilitating the production of significant quantities of these amino acids.

Saturated nitrogen heterocycles

“…Constrained phenylalanine mimics 333 (n = 2, 3) have been synthesized in only five steps from 1-bromo-2-iodobenzene as shown in Scheme 104. 199 The key step involved the intramolecular Heck reaction of bromide 332, a reaction that only works well in the presence of PPh 4 Cl.…”

Divergent Pd-Catalyzed and Radical Cyclizations of Nucleophilic Cyclic Enamines Derived from Functionalized Amine and Aldehyde Fragments

“…The choice of amine 11 as a convenient starting material was dictated by its ready availability in multigram quantities . Aldehydes 2a − c were known compounds, while the preparation of 2d followed the procedure reported for 2c . Tetrahydropyridines 12a − d were then prepared by condensation between 11 and 2a − d in CH 2 Cl 2 at room temperature with the yields indicated in Table .…”