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2-Pyrones (III) and (VII) attached with acrylate or acrylamide dienophiles undergo intramolecular Diels-Alder reaction to give tricyclic products. Treatment of the amide-derived products (VIIIc)-(VIIId) with LiAlH4 or NaOMe furnishes structurally unique cyclohexene ring fused macrocycles (X) and (XII). -(SHIN, J.-T.; SHIN, S.; CHO*, C.-G.; Tetrahedron Lett. 45 (2004) 30, 5857-5860; Dep. Chem., Hanyang Univ., Seoul 133-791, S. Korea; Eng.) -Mais 44-190

One-Pot Synthesis of Piperidines from Imines Using 3-Stannyl-2-(silylmethyl)propene.-The one-pot reaction of aldimines (I) and (V) with 3-stannyl-2-(trimethylsilyl)propene (II), followed by addition of aldehydes is investigated. In the presence of TmsCl as activator single cis isomers of piperidines (IV) are obtained. BF 3 -etherate instead of TmsCl improves significantly the yields of trans products (VII), which are obtained as major isomers. The convenient procedure presented can also be applied to cyclic imines [cf. (VIII)]. The yields of the cycloadducts are higher than in the case of acyclic substrates; however, diastereomeric mixtures of (IX) are formed. -(KANG, K.-T.; KIM, E. H.; KIM, W. J.; SONG, N. S.; SHIN, J. K.; CHO, B. Y.; Synlett (1998) 8, 921-923; Dep. Chem., Pusan Natl. Univ., Pusan 609-735, S. Korea; EN)