Enantioselective Cyclizations of Silyloxyenynes Catalyzed by Cationic Metal Phosphine Complexes

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• 作者：Jean-Fran莽ois Brazeau ; Suyan Zhang ; Ignacio Colomer ; Britton K. Corkey ; F. Dean Toste
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：February 8, 2012
• 年：2012
• 卷：134
• 期：5
• 页码：2742-2749
• 全文大小：582K
• 年卷期：v.134,no.5(February 8, 2012)
• ISSN：1520-5126

文摘

The discovery of complementary methods for enantioselective transition metal-catalyzed cyclization with silyloxyenynes has been accomplished using chiral phosphine ligands. Under palladium catalysis, 1,6-silyloxyenynes bearing a terminal alkyne led to the desired five-membered ring with high enantioselectivities (up to 91% ee). As for reactions under cationic gold catalysis, 1,6- and 1,5-silyloxyenynes bearing an internal alkyne furnished the chiral cyclopentane derivatives with excellent enantiomeric excess (up to 94% ee). Modification of the substrate by incorporating an 伪,尾-unsaturation led to the discovery of a tandem cyclization. Remarkably, using silyloxy-1,3-dien-7-ynes under gold catalysis conditions provided the bicyclic derivatives with excellent diastereo- and enantioselectivities (up to >20:1 dr and 99% ee).