A metal-free one-pot cascade synthesis of highly functionalized biaryl-2-carbaldehydes
作者:Chandrasekhar Challa、Jamsheena Vellekkatt、Jaice Ravindran、Ravi S. Lankalapalli
DOI:10.1039/c4ob01829j
日期:——
A metal-free one-pot cascade annulation of acyclic substrates dienaminodioate, cinnamaldehydes and allyl amine was achieved for the synthesis of polyfunctional biaryl-2-carbaldehydes. The reaction proceeds at room temperature by a trifluoroacetic acid mediated Diels–Alder pathway. Synthetic applications of the resulting biaryl-2-carbaldehyde have been demonstrated by conversion into an array of diverse
The conjugate aldehydes, containing terminal acetylenes, were converted to the corresponding conjugated azines 6a–c and 8a–c, respectively. Oxidative couplings of these azines were attempted. The azines 6b, 6c, and 8b afforded the corresponding cyclic dimers 9, 10, and 11, respectively. Examination of 1H NMR spectra indicates that the tetraazaannulenes are atropic.