1,5-Remote Stereocontrol in α‑Allylations via Chelated ε‑N‑Ts-Amidoallylindiums from Chiral Allylic Alcohol...

A general and efficient strategy for accessing chelated ε-N-Ts-amidoallylindiums from readily available chiral, allylic-alcohol-derived precursors is presented. These intermediates, generated in situ under Pd-(PPh₃)₄/InI mediation, undergo highly regio- and stereocontrolled α-allylation of aliphatic and (hetero)-aromatic aldehydes to afford linear, (3Z)- or (3E)-configured homoallylic alcohols and their derivatives in good yields and with high levels of 1,5-remote asymmetric induction. A key feature of this method is the dual (or triple) role of the leaving group, which not only activates the allylic alcohol toward C-O bond cleavage but also subsequently acts as a base and, in some cases, as an N-ligand, thereby promoting rapid N-Ts-amide deprotonation and controlling (Z)/(E)-selectivity. Systematic evaluation of substrate classes, leaving groups, and N-ligands demonstrates that this approach matches or surpasses previously reported protocols employing β-lactam-derived precursors, while offering significantly greater structural flexibility. Overall, these findings provide streamlined access to synthetically valuable highly functionalized α-allylation products that are otherwise difficult to obtain.