A palladium‐catalyzed intermolecular dynamic kinetic asymmetric dearomatization of 3‐arylindoles with internal alkynes was developed with the use of achiral Xantphos and chiral sulfinamide phosphine ligand (PC‐Phos) as the co‐ligands. This method could deliver various spiro[indene‐1,3′‐indole] compounds in good yields (up to 95 % yield) with up to 98 % ee. The salient features of the transformation
Total synthesis of 27-hydroxy-bullatacin and its C-15 epimer, and studies on their inhibitory effect on bovine heart mitochondrial complex I functions
作者:Zhiyong Chen、Subhash C. Sinha
DOI:10.1016/j.tet.2007.11.089
日期:2008.2
The total synthesis of 27-hydroxybullatacin and its C-15 epimer has been achieved using rhenium(VII) oxides-mediated and Co(modp)(2)-catalyzed oxidative cyclization (OC), diastereoselective alkynylation, Brown's enantioselective allylboration, and Grubbs' cross metathesis as the key reactions. The inhibitory effect of these compounds on the complex I function, as determined by using bovine submitochondrial particles, was in low nanomolar range. (C) 2007 Elsevier Ltd. All rights reserved.
Synthesis of 10 stereochemically distinct bis-tetrahydrofuran intermediates for creating a library of 64 asimicin stereoisomers
作者:Zhiyong Chen、Subhash C. Sinha
DOI:10.1016/j.tetlet.2009.08.082
日期:2009.11
Stereoselective synthesis of 10 unique bifunctional stereoisomeric adjacent bis-THF intermediates (R = Bz), including 5.1-5.4, 5.7-5.9, 5.11, and 5.15-5.16, of 16 possible compounds, is described. The key steps used in the synthesis of these compounds included the rhenium(VII) oxide-mediated and the Co(modP)(2)-catalyzed trans oxidative cyclizations (OCs), the OsO4-catalyzed cis OC, and the Williamson's type etherification reactions. The remaining six bis-THF intermediates (R = Bn) can be prepared from 5.7-5.9, 5.11, and 5.15-5.16 (R = Bz) in two steps, including protection of the free alcohol as benzyl ether followed by the benzoate deprotection. These intermediates should provide access to all 64 asimicin stereoisomers; and their analogs. (C) 2009 Published by Elsevier Ltd.
HOPF, H.;KIRSCH, R., TETRAHEDRON LETT., 1985, 26, N 28, 3327-3330