932380-41-1Relevant articles and documents
Formation and heron reactivity of cyclic n,n-dialkoxyamides
Glover, Stephen A.,Rosser, Adam A.,Taherpour, Avat,Greatrex, Ben W.
, p. 507 - 520 (2014/04/03)
Cyclic N,N-dialkoxyamides have been made, for the first time, by hypervalent iodine oxidation of β- and γ-hydroxyhydroxamic esters 17, 19, and 21. The fused γ-lactam products, N-butoxy- and N-benzyloxybenzisoxazolones (22a and 22b), are stable while alicyclic γ-lactam and d-lactam products, 24 and 25, although observable by NMR spectroscopy and ESI-MS are unstable at room temperature, undergoing HERON reactions. The γ-lactam 24 undergoes exclusive ring opening to give a butyl ester-functionalised alkoxynitrene 28. The δ-lactam 25, instead, undergoes a HERON ring contraction to give butyrolactone (27). The structures of model γ- and δ-lactams 6, 7, and 8 have been determined at the B3LYP/6-31G(d) level of theory and the γ-lactams are much more twisted than the acyclic N,Ndimethoxyacetamide (5) resulting in a computed amidicity for 6 of only 25% that of N,N-dimethylacetamide (3). The HERON reactions of N,N-dimethoxyacetamide (5) and alicyclic models 6 and 8 have been modelled computationally. The facile ring opening of 6 (EA=113 kJ mol -1) and ring contraction of 8 (EA=145 kJ mol-1) are predicted well, when compared with the HERON rearrangement of 5 (EA=178 kJ mol-1). CSIRO 2014.
