Highly enantioselective addition of linear alkyl alkynes to linear aldehydes
作者:Yuhao Du、Mark Turlington、Xiang Zhou、Lin Pu
DOI:10.1016/j.tetlet.2010.07.082
日期:2010.9
It is discovered that the use of biscyclohexylamine (Cy(2)NH) as an additive can greatly enhance the enantioselectivity for the reaction of linear alkyl alkynes with linear aldehydes. The combination of (S)-BINOL (20 mol %), Cy(2)NH (5 mol %), ZnEt(2) (2 equiv), and Ti(O(i)Pr)(4) (0.5 equiv) catalyzes the reaction at room temperature in diethyl ether solution with 81-89% ee and 57-77% yield. (C) 2010 Elsevier Ltd. All rights reserved.
Total Synthesis of the Alkoxydioxines (+)- and (−)-Chondrillin and (+)- and (−)-Plakorin via Singlet Oxygenation/Radical Rearrangement
作者:Patrick H. Dussault、C. Todd Eary、Kevin R. Woller
DOI:10.1021/jo981128q
日期:1999.3.1
unaffected by the presence of polar co-solvents or by the incorporation of a group able to selectively hydrogen bond to the product hydroperoxide. Photoisomerization of the (E)-4-hydroperoxy-2-enone rearrangement products results in irreversible ring closure to furnish diastereomeric mixtures of enantiomericallyenriched dioxinols. The strategy is applied to the total synthesis of the alkoxydioxine natural