The copper-catalyzed reaction of allenes with bis(pinacolato)diboron and acyl electrophiles is reported. In this transformation, acyl fluorides have been proven to be more efficient coupling partners than their chloride or carboxylate analogues. The optimized reaction conditions employed were shown to be compatible with a range of commonly used functional groups, thereby allowing the formation of a library of β-boryl β,γ-unsaturated ketones by varying the nature of the allene and acyl fluoride substrates.

A simple protocol is described for the synthesis of amido and phenyl hexahydroindolizin-3(2H)-one, hexahydro-1H-quinolizin-4(6H)-one, and 1,3,4,10b-tetrahydropyrido[2,1-a]isoindol-6(2H)-one derivatives via endo-trig (aza-Prins type) cyclization followed by an intermolecular Ritter/Friedel-Crafts reaction of cyclic N-acyliminium ions, which are derived from the boron trifluoride etherate treatment of regioselectively reduced N-homoallyl imides. The reactions are highly diastereoselective with excellent yields.

Synthesis of carbonate esters by carboxymethylation using NaAlO2 as a highly active heterogeneous catalyst. ChemRxiv. Preprint. Sodium aluminate is presented as a highly active heterogeneous catalyst able to convert a range of alcohols into the corresponding mixed carbonate esters, in high yield and under green conditions. The reaction is carried out using dimethyl carbonate both as a reactant and solvent, at 90°C. Allylic, aliphatic and aromatic alcohols are converted in good yields. The solid catalyst is shown to be truly heterogeneous, resistant to leaching, and recyclable. File list (3) download file view on ChemRxiv Ramesh NaAlO2 carboxymethylation-preprint.pdf (876.15 KiB) download file view on ChemRxiv graphical abstract.jpg (71.26 KiB) download file view on ChemRxiv Ramesh NaAlO2 carboxymethylation-ESI.pdf (2.05 MiB)

No abstract

Intramolecular hydroalkoxylation/hydrothioalkoxylation of nitrogen-tethered alkenes and alcohols/thiols mediated by boron trifluoride etherate leads to five-membered thiazolidine, six-membered 1,4-oxazines (morpholines) and tetrahydro-2H-1,4-thiazines (thiomorpholines), and seven-membered 1,4-oxazepanes in good yields.