the dual electrophilic properties of (2-chloro-2-nitroethenyl)benzenes in a one-pot, formal [3+2] cycloaddition. Using a base (DBU), the desired trisubstituted heterocycles were formed rapidly (10–30 min) in good to excellent yields (51–92 %), and this versatile, metal-free methodology was applied to the synthesis of 2-acyl- and 2-carboalkoxyfurans and furan-2-carboxamides. Additionally, by using 2-ketophosphonate
leading to the title products as single diastereomers with enantiomeric excesses from 86% up to 97%. Alkyl 4,5-dihydrofuran-2-carboxylates can be efficiently obtained via an enantioselective organocatalyzed consecutive reaction between α-keto esters and (Z)-(2-chloro-2-nitroethenyl)benzenes. The overall sequence combines a (R,R)-TUC-catalyzed Michael addition with a DABCO-promoted intramolecular O-alkylation
cell surface aminopeptidase N (APN/CD13), overexpressed in tumor cells, plays a critical role in angiogenesis. However, potent, selective, and, particularly, noncytotoxic inhibitors ot this protein are lacking, and the present work was undertaken with the aim of developing a new generation of noncytotoxic inhibitors that bind to APN/CD13. In this context, we have synthesized a series of novel flavone-8-acetic