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Diastereoselective Synthesis of Highly Constrained Spiro-β-Lactams by the Staudinger Reaction Using an Unsymmetrical Bicyclic Ketene

✍ Scribed by Andrea Trabocchi; Claudia Lalli; Francesco Guarna; Antonio Guarna


Publisher
John Wiley and Sons
Year
2007
Tongue
English
Weight
156 KB
Volume
2007
Category
Article
ISSN
1434-193X

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✦ Synopsis


Abstract

A rigid bicyclic ketene was used to generate highly constrained polycyclic spiro‐β‐lactams through the Staudinger reaction. Depending on the imine component, high diastereoselectivity was observed in the process, leading to mainly the cis diastereoisomer in the case of aromatic imines. This results from an anti addition of the imine to the ketene, followed by a conrotatory ring closure in which the heteroatom at the 6‐position of the scaffold rotates outward because of torquoelectronic effects.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)