title: Intramolecular Acylal Cyclisation (IAC) as an Efficient Synthetic Strategy towards the Total Synthesis of Erythrina Alkaloid Derivatives.
abstract: Compounds that comprise the erythrina alkaloid class of natural products are based on a tetracyclic spiroamine framework and exhibit a range of biological activities on the central nervous system. Herein, we report a new and efficient total synthesis of this multiple-ring system based on an intramolecular acylal cyclisation (IAC) approach. Using this methodology, the tetracyclic core was rapidly assembled over a two-step domino process catalysed by a Lewis acid. The effect of heteroatoms, substituents and ring size on the IAC has also been investigated, and the broad application of this procedure is demonstrated by the synthesis of a library of derivatives in good yields with excellent regioselectivity.
authors.affiliation: UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX (UK).
authors.forename: Alessandra
authors.initials: A
authors.lastname: Monaco
authors.affiliation: Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ (UK).
authors.forename: Abil E
authors.initials: AE
authors.lastname: Aliev
authors.affiliation: UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX (UK). s.hilton@ucl.ac.uk.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Hilton
keywords: Lewis acid; acylal; erythrina alkaloids; intramolecular acylal cyclisation; tandem cyclisation