Synthesis of Spiropyrrolidines and Spiropyrrolizidines by Azomethine Ylide Cycloaddition of Baylis-Hillman Adducts Derived from N-Methyl Maleimide - Karthikeyan, K.; Saranya, N.; Kalaivani, A.; Perumal, P. T. (Synlett, 2010)