A simple and efficient cascade synthesis was achieved to produce chloro substituted 9-phenyl-6H-benzo[c]chromenes under mild and additive-free reaction conditions via chlorination followed by benzannulation. This would be a green alternative approach to introduce a chlorine atom on poly hetero aromatic rings without use of other toxic and malodorous chlorinating agents. The core structure is a part
The first Pd/C-mediated Sonogashira coupling of beta-chloroacroleins with terminal alkynes is described here. Pd/C-CuI-PPh3 was found to be an efficient catalyst system for this coupling reaction. Using this economic and general process a variety of 4-alkynyl-2H-chromene-3-carbaldehydes and 5-alkynyl-2,3-dihydro benzo[b]oxepine-4-carbaldehydes were prepared in good yields. (c) 2007 Elsevier Ltd. All rights reserved.