Common oxidants used in chemical synthesis, including newly developed perruthenates, were evaluated in the context of understanding (and better appreciating) the sensitiveness and associated potential hazards of these reagents. Analysis using sealed cell differential scanning calorimetry (scDSC) facilitated Yoshida correlations, which were compared to impact sensitiveness and electrostatic discharge experiments (ESD), that enabled sensitiveness ranking. Methyltriphenylphoshonium perruthenate (MTP3, 8), isoamyltriphenylphosphonium perruthenate (ATP3, 7) and tetraphenylphosphonium perruthenate (TP3, 9) were found to be the most sensitive followed by 2‐iodoxybenzoic acid (IBX, 2) and benzoyl peroxide (BPO, 10), whereas the most benign were observed to be Oxone (12), manganese dioxide (MnO2, 13), and N‐bromosuccinimide (NBS, 17).
Chemistry-A European Journal Scheme3.Construction of the ethoxy tetrahydrobenzofurans 30 and 31. Scheme4.Constructiono fthe advanceds keletal framework via rhodium catalyzed [4+ +3] cycloaddition,with incorporationo ft he A-ring exocyclic double bond.
The authors became aware of am istakei nF igure 3o ft he above-mentioned manuscript.T he y-axis of the Figure was incorrectly labelled "Q DSC (J g À1)" and should thus be labelled "Q DSC (cal g À1)". Anew Figure 3i ss hown below. Additionally,d uring production of the graphic, the data point labelled "CAN" was placed with ay-value of 569 cal g À1 rathert han the correct value of 677 cal g À1 .T his error arose during conversion of the Jg À1 measured by the DSCi nstrumentt oc al g À1 for application in the Yoshida correlation equations, in which at ypo of 2383 Jg À1 was used insteado f2 833 Jg À1 .T he correctc al g À1 value of 677 cal g À1 appears in Ta ble 1a nd in the text, so the error is only present in Figure 3. This correction does not alter in any way the analysisa nd conclusions drawn in the article. The authors apologize for this error andf or any inconvenience caused.
Tandem oxidative-dehydrogenation of primary alcohols to give α,β-unsaturated aldehydes in one pot are rare transformations in organic synthesis, with only two methods currently available. Reported herein is a novel method using the bench-stable salt methyltriphenylphosphonium perruthenate (MTP3), and a new co-oxidant NEMO·PF6 (NEMO = N-ethyl-N-hydroxymorpholinium) which provides unsaturated aldehydes in low to moderate yields. The Ley-Griffith oxidation of (hetero)arylated primary alcohols with N-oxide co-oxidants NMO (NMO = N-methylmorpholine N-oxide)/NEMO, is expanded by addition of the N-oxide salt NEMO·PF6 to convert the intermediate saturated aldehyde into its unsaturated counterpart. The discovery, method development, reaction scope, and associated challenges of this method are highlighted. The conceptual value of late-stage dehydrogenation in natural product synthesis is demonstrated via the synthesis of a polyene scaffold related to auxarconjugatin B.
The rhodium(II)-catalyzed reaction of a model alkenyl donor/ acceptor N-sulfonyltriazole with a wide selection of furans is reported. This investigation unearthed a range of structurally diverse carbocyclic and ring-opened products, in good to excellent yields. The products obtained are proposed to arise selectively via cyclopropanation or zwitterionic rearrangement pathways, which are highly dependent on both the structural and electronic features of the furan substrate.
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