Gold‐Catalyzed [2+2+1] Cycloaddition of 1,6‐Diyne Carbonates and Esters with Aldehydes to 4‐(Cyclohexa‐1,3‐dienyl)‐1,3‐dioxolanes |
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Authors: | Dr Weidong Rao Prof?Dr Philip Wai Hong Chan |
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Institution: | Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore), Fax: (+65)?6791‐1961 |
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Abstract: | A synthetic method to stereoselectively prepare 4‐(cyclohexa‐1,3‐dienyl)‐1,3‐dioxolanes in good to excellent yields by gold(I)‐catalyzed 2+2+1] cycloaddition of 1,6‐diyne carbonates and esters with aldehydes is described. The cascade process involves 1,2‐acyloxy migration followed by cyclopropenation and cycloreversion. This leads to an unprecedented 2+2+1] cycloaddition of the resulting alkenylgold carbenoid species, examples of which are extremely rare, with two aldehyde molecules at catalyst loadings as low as 1 mol %. The usefulness of this cycloisomerization chemistry was further demonstrated by the transformation of one example to the corresponding phenol. |
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Keywords: | aldehydes cycloaddition gold homogenous catalysis propargylic compounds |
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