Synthesis and characterization of novel 1,3-selenazine derivatives. BF3 center dot Et2O-assisted reaction of primary selenoamides with alpha,beta-unsaturated ketones

Reaction of primary selenoamides with alpha,beta-unsaturated ketones in the presence of BF3. Et2O provided 5,6-dihydro-4H-1,3-selenazine derivatives i n high yields. Among the 1,3-selenazine diastereomers bearing two asymmetri c carbons at the C4 and C6 positions, the cis form is predominant.