Simple access to 5-carboalkoxy-2,3-dihydro-4H-pyran-4-ones via domino acylative electrocyclization: the first three step total synthesis of the dihydronaphthopyran-4-one class of natural products?

RSC Advances Pub Date: 2014-10-17 DOI: 10.1039/C4RA11174E

Abstract

Intermolecular domino C-acylation/6π-oxaelectrocyclization between β-ketoesters and α,β-unsaturated acid chlorides took place readily in the presence of CaCl2 to afford a variety of polysubstituted 5-carboalkoxy-2,3-dihydro-4H-pyran-4-ones, in good yields. The products were successfully exploited as precursors, for a simple and efficient construction of a naphthalene fused pyran-4-one ring system. This intramolecular Friedel–Crafts acylative aromatization approach was useful for the synthesis of the phytogrowth inhibiting dihydronaphthopyranone class of natural products.

Graphical abstract: Simple access to 5-carboalkoxy-2,3-dihydro-4H-pyran-4-ones via domino acylative electrocyclization: the first three step total synthesis of the dihydronaphthopyran-4-one class of natural products
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