Purpose: Radiation oncologists need to have more than sound clinical and technical competencies. To optimize care for patients and advance all aspects of radiation oncology (RO), radiation oncologists must also be effective leaders. Embedding systematic leadership education into RO training programs is challenging.
View Article and Find Full Text PDFA sequential three-component cascade process was developed for the synthesis of bridged tetrahydroquinolines and chromanes bearing 2,6-methanobenzo[][1,3]diazocine and 2,6-methanobenzo[][1,3]oxazocine scaffolds, respectively, in good yields from readily available materials. The InCl-catalyzed reaction progressed via enamine formation, Michael addition, intramolecular cyclization, and intramolecular iminium ion cyclization steps. Notably, this high atom economic approach (-2HO) allowed the generation of four new bonds (1 C-C and 3 C-N or 1 C-C, 1 C-O and 2 C-N) and two heterocyclic rings in a single operation.
View Article and Find Full Text PDFAn oxidant-free three-component synthesis of biologically significant 7-amino-6-benzo[]chromen-6-ones was established involving a Sc(OTf) catalyzed three-component reaction between primary amines, β-ketoesters and 2-hydroxychalcones under green conditions. In this strategy, both the B and C rings of 6-benzo[]chromen-6-ones were constructed simultaneously starting from acyclic precursors by generating four new bonds including two C-C, one C-N and one C-O in a single synthetic operation. The mechanism of this sequential cascade process involves the initial formation of a β-enaminone intermediate followed by Michael addition with 2-hydroxychalcone, intramolecular cyclization, dehydration, lactonization and aromatization steps.
View Article and Find Full Text PDFAn efficient Pd(II)-catalyzed cascade approach was established for the synthesis of 9-chloro-1-benzo[]furo[3,4-]azepin-1-ones starting from -propargyl arylamines having a pendant α,β-unsaturated ester scaffold. The mechanism of this sequential process involved intramolecular -oxypalladation followed by olefin insertion and sp-C-Cl bond formation reactions. This high atom- and step-economical cascade sequence generated two heterocycle rings and three new bonds in a single synthetic operation.
View Article and Find Full Text PDFAn efficient green protocol for the synthesis of complex hybrid heterocycles containing [1,6]-naphthyridine and coumarin/pyrazole moieties was established, involving an intramolecular [4 + 2] hetero Diels-Alder reaction as the key step. The biologically significant 12,13-dihydro-6H-benzo[h]chromeno[3,4-b][1,6]naphthyridin-6-ones and 6,10-dihydro-5H-benzo[h]pyrazolo[3,4-b][1,6]naphthyridines were synthesized starting from 2-(N-propargylamino)-arylaldehydes and 3-aminocoumarins or 3-methyl-1-aryl-1H-pyrazol-5-amines in the presence of an Amberlyst-15 catalyst in PEG-200 in good yields. The easy access to diverse complex molecules in a single operation from readily available starting materials, a commercially available, transition metal-free and recyclable catalyst, the use of a green solvent, a very high atom economy and the release of water as the only side product are the highlights of this protocol.
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