Claisen Rearrangements of Allylic and Propargylic Alcohols Prepared by an N-Boc-2-acyloxazolidine Methodology − Application to the Synthesis of Original Chiral Building Blocks
作者:Claude Agami、François Couty、Gwilherm Evano
DOI:10.1002/1099-0690(20021)2002:1<29::aid-ejoc29>3.0.co;2-b
日期:2002.1
protecting group occurs stereoselectively. The resulting α,β-epoxyoxazolidines are then transformed into trisubstituted stereodefined cyclopropanes. Claisen rearrangements of propargylic alcohols, on the other hand, stereoselectively give α-allenyloxazolidines. These compounds follow a different pathway to α-alkenyloxazolidines as regards bromocarbamation. An original route to enantiopure 3-hydrox
由衍生自 (R)-苯基甘氨醇的 Weinreb 酰胺分两步制备的立体定义的烯醇经历高度立体选择性的克莱森重排。然后可以回收和还原生成的 N-Boc-烯基恶唑烷的掩蔽醛部分,无需差向异构化,以产生新的对映体纯手性结构单元。或者,这些 N-Boc-2-烯基恶唑烷通过涉及 Boc 保护基团的成熟分子内溴氨基甲酸酯的环氧化反应立体选择性地发生。然后将所得的 α,β-环氧恶唑烷转化为三取代的立体定义的环丙烷。另一方面,炔丙醇的克莱森重排立体选择性地得到α-烯丙基恶唑烷。这些化合物在溴代氨基甲酸酯化方面遵循不同的 α-烯基恶唑烷途径。