Stereospecific Rhodium-Catalyzed Allylic Substitution with Alkenyl Cyanohydrin Pronucleophiles: Construction of Acyclic Quaternary Substituted 伪,尾-Unsaturated Ketones

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• 作者：Ben W. H. Turnbull ; Samuel Oliver ; P. Andrew Evans
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：December 16, 2015
• 年：2015
• 卷：137
• 期：49
• 页码：15374-15377
• 全文大小：363K
• ISSN：1520-5126

文摘

A highly regio- and stereospecific rhodium-catalyzed allylic alkylation of tertiary allylic carbonates with alkenyl cyanohydrin pronucleophiles is described. This protocol offers a fundamentally novel approach toward the synthesis of acyclic quaternary-substituted 伪,尾-unsaturated ketones and thereby provides a new cross-coupling strategy for target directed synthesis. A particularly attractive feature with this process is the ability to directly couple di-, tri- and tetrasubstituted alkenyl cyanohydrin pronucleophiles to prepare the corresponding 伪,尾-unsaturated ketone derivatives in a highly selective manner. Additionally, the chemoselective 1,4-reduction of the enone products provides rapid access to acyclic enantiomerically enriched 伪,伪鈥?dialkyl-substituted ketones, which are challenging motifs to prepare using conventional enolate alkylation.