A visible-light Paternò-Büchi dearomatisation process towards the construction of oxeto-indolinic polycycles
Javier Mateos1, Alberto Vega-Peñaloza1, Pietro Franceschi1
1Department of Chemical Sciences, University of Padova Via Marzolo 1 35131 Padova Italy luca.dellamico@unipd.it xavier.companyo@unipd.it.
Abstract:
A variety of highly functionalised N-containing polycycles (35 examples) are synthesised from simple indoles and aromatic ketones through a mild visible-light Paternò-Büchi process. Tetrahydrooxeto[2,3-b]indole scaffolds, with up to three contiguous all-substituted stereocenters, are generated in high yield (up to >98%) and excellent site- regio- and diastereocontrol (>20 : 1). The use of visible light (405 or 465 nm) ensures enhanced performances by switching off undesired photodimerisation side reactions. The reaction can be easily implemented using a microfluidic photoreactor with improved productivity (up to 0.176 mmol h-1) and generality. Mechanistic investigations revealed that two alternative reaction mechanisms can account for the excellent regio- and diastereocontrol observed.
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