The reaction of α- and ω-methylenelactams with nitrones. Influence of electronic and geometric factors on the stereoselectivity of their 1,3-dipolar cycloaddition
Abstract
Various four to six-membered ring α- and ω-methylenelactams 1–5 were reacted with nitrones 6 and afforded good yields of spiroadducts 7–12 through a regiospecific [3 + 2] cycloaddition. Owing to the creation of at least two new asymmetric centres, mixtures of diastereoisomers were usually obtained whose structures were established by two-dimensional