Heck-oxyarylation of 2-phenyl-2H-chromenes and 1,2-dihydronaphthalenes
摘要:
The Heck-oxyarylation of racemic 2-phenyl-2H-chromene [(+/-)-4b] and 1,2-dihydronaphthalenes (14a,b) has been studied with 2-chloromercuriphenols (5a-d) in the presence of Li-2[PdCl4] catalyst. The reactions resulted in the diastereoselective formation of racemic 6-phenylpterocatpans of (6R, 6aR,11aR) relative configuration [(+/-)-8a-d] and their dibenzo[1,3]dioxocine analogues [(+/-)-12a-d] as main products, respectively. The ratio of products and the lack of regioisomeric products (13a-d) corroborated the cationic mechanism of the oxyarylation of 2H-chromenes, which has been also supported by the transformation of 14a,b under similar conditions.