1,3-Dipolar cycloaddition reaction of α,β-unsaturated esters and lactones with diazomethane

Article abstract of DOI:10.1016/0040-4020(96)00099-3

1,3-Dipolar cycloaddition of diazomethane to the α,β-unsaturated esters and lactones such as 2-4, 6-8, 10 and 13 occurs in a stereoselective manner affording conjugated Δ²-pyrazolines. E and Z isomers of D-mannitol lead to identical product which was cyclised to investigate the absolute stereochemistry of the product. The regiospecificities of all the reactions are consistent with FMO coefficients obtained through AM1 calculations.