the 5-endo-trig cyclization of d-glucose derived γ-alkenylamines with mercury (ii) salts synthesis of 1-deoxycastanospermine and its 8a-epi-analogue？5-endo-trig环化的葡萄糖派生γ-alkenylamines 1-deoxycastanospermine汞(二)盐的合成及其8 a-epi-analogue .pdf

Molecules 2005, 10, 893-900 molecules ISSN 1420-3049 The 5-Endo-trig Cyclization of D-Glucose Derived γ-Alkenylamines with Mercury (II) Salts: Synthesis of 1-Deoxy- castanospermine and its 8a-epi-Analogue† Dilip D. Dhavale* and Santosh M. Jachak Department of Chemistry, Garware Research Centre, University of Pune, Pune- 411 007, India. Fax (+91) 20 * Author to whom correspondence should be addressed; e-mail ddd@chem.unipune.ernet.in. † Dedicated to Prof. K.K. Balasubramanian on the occasion of his 65th birthday. Received: 15 October 2004; in revised form: 4 January 2005 / Accepted: 10 January 2005 / Published: 31 August 2005 Abstract: The intramolecular aminomercuration of γ-alkenylamines 1a, 1b and 4 was shown to afford the 5-endo-trig cyclized product exclusively in good yield. The utility of pyrrolidine derivatives thus obtained from D-glucose derived γ-alkenylamines 1a and 1b was demonstrated in the synthesis of 1-deoxycastanospermine (3a) and 1-deoxy-8a-epi- castanospermine (3b). Keywords: Aminosugars, aminomercuration, alkaloids, enzyme inhibitors, nitrones. Introduction The pyrrolidine ring skeleton constitutes an important molecular backbone for a number of heterocyclic compounds. Among the strategies available for the synthesis of pyrrolidine ring skeletons one of the most attractive is the stereoselective intramolecular amido- and/or amino-mercuration reaction of δ−alkenylamines [1]. The reaction affords 2-substituted pyrrolidine rings through preferred 5-exo-trig cyclization, in addition to the 6-endo-trig cyclized piperidine ring skeleton in minor amounts [2].