Exerting control over the acyloin reaction

Abstract

A synthetic method for conducting the acyloin reaction using electron transfer in solution is reported. By linking two esters via their oxygen atoms, it was possible to perform crossed acyloin reactions between two different ester functionalities and display a high degree of preference for an intramolecular coupling process.

Synthesis of norbornane bisether antibiotics via silver-mediated alkylation

“…43 Unfortunately, in the current work, after acetylation of diol 6 to form diacetate 20 (63%, see experimental section), 41 reaction with InBr 3 failed to produce the bisether product; instead 1 H NMR analysis indicated that a complex mixture of products had formed.…”

“…39 The syn -1,2-diol 6 was synthesized in excellent yields (94%) on multigram scales (up to 4 g), using OsO 4 (0.1 mol%) mediated dihydroxylation of the norbornene using 4-methylmorpholine N -oxide (NMO) as a co-oxidant. 16, 40 Dihydroxylation using KMnO 4 , as detailed by Donohoe, 41 was also successful, albeit in lower yield (58%) (see Supporting Information for full reaction conditions).…”

“…The following compounds were prepared using literature methods and full reaction details can be found in the supplementary information; Dimethyl bicyclo[2.2.1]hept-5-ene-3- endo -2- exo -dicarboxylate ( 17 ), 39, 51 6 16, 41 and 14 . 47 …”

Development Of New Routes For The Synthesis Of Carbaporphyrins And Carbachlorins

“…Donohoe and coworkers reported an alternative two steps route to dialdehydes. 59 In this synthetic route, a solution of norbornadiene 111 in tert-butyl alcohol was oxidized to give 112 using KMnO4 and NaOH in tert-butyl alcohol and water at 0 o C (Scheme 47). 59 However, when we attempted to prepare 112 using this methodology, the yields were low.…”

“…The mixture was filtered and the tert-butyl alcohol was removed from the filtrate in vacuo. The remaining solution was extracted with ethyl acetate which was filtered and concentrated in vacuo to yield dialcohol 137 as white crystalline solid (Scheme 69) 59. Compound 137 had not been prepared previously and was synthesized for the first time.Scheme 69 Formation of Dialdehyde 134 Diol 137 could be oxidatively ring opened using potassium periodate as an oxidizing agent to give dialdehyde 134.…”