Gold(I)-Promoted Heterocyclization of Internal Alkynes: A Comparative Study of Direct Metallate <i>5-endo-dig</i> Cyclization versus a Stepwise Cyclization
作者:Jonathan M. French、Steven T. Diver
DOI:10.1021/jo500748e
日期:2014.6.20
additional normal alkyl substituents at the propargylic position gave dehydropiperidines as the major product. This pathway is thought to proceed by way of a 1,2- Rautenstrauch rearrangement to produce a vinyl gold(I) carbene, which undergoes conjugate addition by the nitrogen pronucleophile. Structural and electronic factors were studied in the nitrogen pronucleophile and in the migrating acyloxy group. Each
使用阳离子金催化剂,发现同时带有炔丙基酰氧基和甲苯磺酰胺亲核试剂的内部炔烃环化生成五元或六元环氮杂环。检查了各种各样的金催化剂,抗衡离子和溶剂,以阐明它们对产物分布的影响。在大多数情况下,直接的5- end发现dig-dig环化是导致脱氢吡咯烷产物的良好收率的主要途径。在炔丙基位置带有另外的正烷基取代基的炔烃底物得到脱氢哌啶作为主要产物。该途径被认为是通过1,2-Rautenstrauch重排进行的,以产生乙烯基金(I)卡宾,其通过亲核原氮进行共轭加成。在氮亲核试剂和迁移的酰氧基中研究了结构和电子因素。发现每种都对产物比率有较小的影响。