Gold(I)-catalysed tandem cyclization of propargyl acetals and alkynes

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• 作者：Huey-San Melanie Siah ; Morten Christian Hogsnes ; Naseem Iqbal ; Anne Fiksdahl ; ^{anne.fiksdahl@chem.ntnu.no" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Propargyl acetal ; Gold(I) catalysis ; Tandem cycloadditions ; Alkyne ; Pentalene
• 刊名：Tetrahedron
• 出版年：2016
• 出版时间：25 February 2016
• 年：2016
• 卷：72
• 期：8
• 页码：1058-1068
• 全文大小：1003 K

文摘

To expand the understanding of the chemistry of propargyl acetals, their gold(I) catalysed cycloaddition reactions with alkynes have been investigated. We hereby report a novel tandem reaction that allows the construction of a new type of polysubstituted and highly functionalised bicyclic pentalene compounds, 2,6a-dimethoxy-3a-methyl-1,4,5-triphenyl-1,3a,4,6a-tetrahydropentalenes, with four stereogenic centres.

Pure diastereomers were successfully isolated in up to 51% yield from mixtures of diastereomeric products (up to 60% total yield) and characterized individually by NMR spectroscopy. A plausible mechanism for the formation of these novel tandem products, based on subsequent [2+2] and [2+3] cycloadditions, is proposed for this gold(I) catalysed reaction.