Stereoselective synthesis of complex polycyclic aziridines: use of the Brønsted acid-catalyzed aza-Darzens reaction to prepare an orthogonally protected mitomycin C intermediate with maximal convergency
作者:Jayasree M. Srinivasan、Priya A. Mathew、Amie L. Williams、John C. Huffman、Jeffrey N. Johnston
DOI:10.1039/c0cc05734g
日期:——
A concise synthesis of a highly functionalized intermediate lacking only C10 of the mitomycin backbone is described. The key to this development is the Brønsted acid-catalyzed aza-Darzens reaction used to forge the cis-aziridine. Additionally an oxidative ketalization fortuitously occurs during the quinone–enamine coupling step, leading to an orthogonally protected hydroquinone.
Selective Oxidation of Propargylic Alcohols into α,β-Acetylenic Aldehydes with a TiCl4/Et3N System
作者:Zhenfu Han、Hiroshi Shinokubo、Koichiro Oshima
DOI:10.1055/s-2001-16807
日期:——
A TiCl4/Et3N combination proved to be effective for the selective oxidation of propargylic alcohols into α,β-acetylenic aldehydes in good yields. Treatment of 2-hexyne-1,6-diol with TiCl4/Et3N provided 6-hydroxy-2-hexynal in good yield.
Diarylprolinol in an Asymmetric, Direct Cross-Aldol Reaction with Alkynyl Aldehydes
作者:Yujiro Hayashi、Masahiro Kojima、Yusuke Yasui、Yuta Kanda、Takasuke Mukaiyama、Hiroki Shomura、Daichi Nakamura、Ritmaleni、Itaru Sato
DOI:10.1002/cctc.201300390
日期:2013.10
The direct cross‐aldol reaction of alkynyl aldehydes catalyzed by a trifluoromethylated diarylprolinol provides a practical route for the highly enantioselective synthesis of chiral β‐alkynyl‐β‐hydroxy aldehydes. Good anti selectivity and excellent enantioselectivity were obtained in the reactions of silylpropynals, which afford synthetically useful chiral building blocks.