The synthesis of furofuranoid lignans

An approach to the synthesis of 2,6-diaryl-8-oxo-3,7-dioxabicyclo [3,3,0] octane lignan lactones is presented and then used in the synthesis of the natural products aptosimon and styraxin. The structure of aptosimon has now been confirmed as having a 2,6-diaryl structure rather than the 2,4-diaryl s...

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Bibliographic Details
Main Author: Stevens, David R.
Format: Thesis (University of Nottingham only)
Language:English
Published: 1989
Online Access:https://eprints.nottingham.ac.uk/13170/
Description
Summary:An approach to the synthesis of 2,6-diaryl-8-oxo-3,7-dioxabicyclo [3,3,0] octane lignan lactones is presented and then used in the synthesis of the natural products aptosimon and styraxin. The structure of aptosimon has now been confirmed as having a 2,6-diaryl structure rather than the 2,4-diaryl structure which has been postulated in the literature. A germination inhibitor MEL, isolated from Aegilops ovata, has also been synthesised. A key ring closing reaction in this strategy was a Lewis acid catalysed directed aldol reaction between a silyl enol ether and an acetal. A review of similar ring closures in the literature is presented. The use of alpha-arylidene lactones as intermediates in lignin synthesis has also been investigated. The stereochemistry of products from reactions used in this strategy was determined and as a result it was possible to successfully design a stereochemically controlled synthesis of dihydrosesamin.