Zinc bromide as catalyst for the stereoselective construction of quaternary carbon: improved synthesis of diastereomerically enriched spirocyclic diols
作者:Yong Qiang Tu、Chun An Fan、Shi Kuo Ren、Albert S. C. Chan
DOI:10.1039/b006182o
日期:——
proved to be a facile and efficient catalyst for the stereoselective semipinacol rearrangement of α-hydroxy epoxides at room temperature. Of note are the presence in the product of two adjacent chiral carbon centers, particularly the creation of a stereoselective quaternary center, and the efficient synthesis of β-hydroxy ketones, including some with naturally occurring spiroalkane skeletons. As an
Stereoselective Reductive Rearrangement of α-Hydroxy Epoxides: A New Method for Synthesis of 1,3-Diols<sup>1</sup>
作者:Yong Qiang Tu、Liang Dong Sun、Ping Zhen Wang
DOI:10.1021/jo981097z
日期:1999.1.1
A novel and short synthetic method for the stereoselective synthesis of 1,3-diols has been developed by an unusual reductive rearrangement of a series of cl-hydroxy epoxides with aluminum isopropoxide. The reaction process was also investigated with deuterium-labeled aluminum isopropoxide, which revealed a site-specific 1,2-carbon-to-carbon migration and successive stereoselective hydride shift. The main synthetically valuable feature is that up to three contiguous carbon centers, the C-1, C-2, and C-3, were stereoselectively controlled with C-2 being quaternary. This reaction is of particular importance to the synthesis of newly developed powerful asymmetric hydrogenation catalysts containing the chiral ligands of spirocyclic diols.