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Stereoselective Synthesis of Lignans of Three Structural Types from a Common Intermediate, Enantioselective Synthesis of (+)‐Yangambin
Author(s) -
Syed Majid Khalil,
Murray Cian,
Casey Mike
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201402584
Subject(s) - chemistry , enantioselective synthesis , aldol reaction , stereoselectivity , ketone , enone , sulfoxide , yield (engineering) , electrophile , total synthesis , organic chemistry , stereochemistry , catalysis , materials science , metallurgy
Enantioselective total synthesis of (+)‐yangambin was achieved. The key transformation is one‐pot conjugate addition/aldol reaction that involves an enantioenriched benzyl tert ‐butyl sulfoxide, an enone, and gaseous formaldehyde to construct the bis(phenylpropanoid) backbone with excellent stereoselectivity and in good yield. Reduction of the ketone with diisobutylaluminium hydride and acid‐catalysed cyclisation in EtOH furnished (+)‐yangambin in good yield. The resulting synthesis is short, efficient and highly selective. Formation of 2,5‐diaryltetrahydrofuran lignans was observed as a side reaction in the final step of yangambin synthesis. Acid‐catalysed cyclisation of the aldol intermediate gave a completely different outcome. Dehydration to give an enone was followed by two electrophilic aromatic substitution reactions to furnish a derivative of the lignan lirionol.