Selective Reductions of Cyclic 1,3-Diesters Using SmI₂ and H₂O

Abstract

SmI(2)-H(2)O reduces cyclic 1,3-diesters to 3-hydroxyacids with no over-reduction. Furthermore, the reagent system is selective for cyclic 1,3-diesters over acyclic 1,3-diesters and esters. Experimental and computational studies suggest that the origin of the selectivity lies in the initial electron transfer to the ester carbonyl and the anomeric stabilization of the resulting radical-anion intermediate. Radicals formed by one-electron reduction of the ester carbonyl group have been exploited in intramolecular additions to alkenes.

Beyond Samarium Diiodide: Vistas in Reductive Chemistry Mediated by Lanthanides(II)

“…[35] We have also developed a selective reduction of Meldrums acids using SmI 2 /H 2 O (Scheme 15). [36] A range of diverse derivatives of Meldrums acids underwent monoreduction to provide the corresponding 3-hydroxy acids in excellent yields. Sensitive functional groups, such as aryl bromides and esters were tolerated, thus underlining the mild reaction conditions possible with the SmI 2 /H 2 O system.…”

“…Selective monoreduction of Meldrum's acids using SmI 2 / H 2 O by Procter and co-workers. [36] Scheme 16. Reductive cyclization of six-membered lactones using SmI 2 /H 2 O by Procter and co-workers: [37,38] A) monocyclizations; B) cyclization cascades.…”

Selective Reductions of Cyclic 1,3‐Diesters by Using SmI2 and H2O

“…[2] Here we report in full our studies on the mono-reduction of cyclic 1,3-diesters with SmI 2 /H 2 O. [3] The reagent system is selective for cyclic 1,3-diesters over acyclic 1,3-diesters, lactones and esters and experimental and computational studies have been used to understand the selectivity. The radical intermediates formed by one electron reduction of the ester carbonyl group have been exploited in intramolecular additions to alkenes.…”

Jenseits von Samariumdiiodid: Perspektiven für Lanthanoid(II)‐vermittelte Reduktionen

“…[35] Außerdem entwickelten wir eine selektive Reduktion der Meldrumsäure mithilfe von SmI 2 /H 2 O (Schema 15). [36] Zahlreiche Derivate der Meldrumsäure erfuhren in hervorragenden Ausbeuten eine Monoreduktion zu den entsprechenden 3-Hydroxysäuren. Empfindliche Gruppierungen, wie Arylbromide und Ester, wurden toleriert, was unterstreicht, dass das SmI 2 /H 2 O-System milde Reaktionsbedingungen ermçg-licht.…”