As part of a study aimed at generating analogues of hyperforin (1), the reaction of this prenylated phloroglucinol with various hydride reducing agents was investigated. Hyperforin contains two beta-dicarbonyl systems, one of which is non-enolizable, and it was interesting to assess the relative reactivity of these structural elements in the highly compact framework of the natural product. Depending on the reducing agent employed, a surprising range of compounds could be obtained, sometimes in synthetically useful yields. The stereochemistry of the LiAlH4-reduced product was secured by X-ray analysis and served as a base for elucidating the configuration of a series of reduced and deoxygenated analogues obtained with other reducing agents. The chemoselectivity observed in these reactions is apparently the result of a combination of metal-chelation and hydrogen-bonding effects. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim., Germany, 2006).
The reaction of hyperforin with hydride reducing agents / L. VEROTTA, O. STERNER, G. APPENDINO, E. BOMBARDELLI, T. PILATI. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1434-193X. - 2006:24(2006), pp. 5479-5484. [10.1002/ejoc.200600644]
The reaction of hyperforin with hydride reducing agents
L. VEROTTAPrimo
;
2006
Abstract
As part of a study aimed at generating analogues of hyperforin (1), the reaction of this prenylated phloroglucinol with various hydride reducing agents was investigated. Hyperforin contains two beta-dicarbonyl systems, one of which is non-enolizable, and it was interesting to assess the relative reactivity of these structural elements in the highly compact framework of the natural product. Depending on the reducing agent employed, a surprising range of compounds could be obtained, sometimes in synthetically useful yields. The stereochemistry of the LiAlH4-reduced product was secured by X-ray analysis and served as a base for elucidating the configuration of a series of reduced and deoxygenated analogues obtained with other reducing agents. The chemoselectivity observed in these reactions is apparently the result of a combination of metal-chelation and hydrogen-bonding effects. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim., Germany, 2006).Pubblicazioni consigliate
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