Rearrangement of Propargylic Esters: Metal-Based Stereospecific Synthesis of (E)- and (Z)-Knoevenagel Derivatives

详细信息    查看全文

• 作者：José ; Barluenga ; Lorena Riesgo ; Rubé ; n Vicente ; Luis A. Ló ; pez ; Miguel Tom&aacute ; s
• 刊名：Journal of the American Chemical Society
• 出版年：2007
• 出版时间：June 27, 2007
• 年：2007
• 卷：129
• 期：25
• 页码：7772 - 7773
• 全文大小：52K
• 年卷期：v.129,no.25(June 27, 2007)
• ISSN：1520-5126

文摘

Alkoxy-substituted propargylic esters undergo regioselective 1,3-acyloxy migration in the presence of Pt(II) and Cu(I) catalysts, allowing the preparation of s/gifchars/alpha.gif" BORDER=0>-ylidene-s/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-keto and -malonate esters. The reaction proved to also be stereodivergent as the Pt(II) and the Cu(I) catalysts perform the isomerization with complementary Z/E selectivity. Moreover, alkynyl-conjugated Knoevenagel products are produced from (bisalkynyl)methyl acetates. In such a case, the reaction is chemoselective as the 1,3-acetyl migration takes place through the alkoxyalkyne group in preference over the phenylalkyne group. The resulting (E)-alkynylenone unit suffers metal-catalyzed cyclization into the furyl ring, generating a copper(I) carbene species.