Practical Enantioselective Synthesis of β-Lactones Catalyzed by Aluminum Bissulfonamide Complexes
作者:Thomas Kull、René Peters
DOI:10.1002/adsc.200700084
日期:2007.7.2
practical aluminum-bissulfonamide complex catalyzed enantioselective formation of β-lactones by [2+2] cycloaddition of ketene (generated in situ from acetyl bromide by dehydrobromination) with various α-unbranched and -branched aliphatic aldehydes is presented. The methodology offers the advantage of operational simplicity not only as the ligand synthesis requires just a single sulfonylation step from commercially
A catalytic enantioselective reaction using a C2-symmetric disulfonamide as a chiral ligand: Alkylation of aldehydes catalyzed by disulfonamide-Ti(O-i-Pr)4-Dialkyl zinc system
Reversal of enantioselectivity on protonation of enol(ate)s derived from 2-methyl-1-tetralone using C2-symmetric sulfonamides
作者:Ewan Boyd、Gregory S. Coumbarides、Jason Eames、Alastair Hay、Ray V.H. Jones、Rachel A. Stenson、Michael J. Suggate
DOI:10.1016/j.tetlet.2004.10.087
日期:2004.12
The synthesis of enantiomerically enriched (R)-2-methyl-1-tetralone 1 (64% e.e.) was achieved through protonation of its lithium enolate 3 using a C-2-symmetrical bis-sulfonamide 5d as an internal proton source. Access to the complementary (S)-enantiomer 1 (45% e.e.) can be achieved using an external quench strategy involving acetic acid as the external proton source. (C) 2004 Elsevier Ltd. All rights reserved.
Catalytic enantioselective cyclopropanation with bis(halomethyl)zinc reagents. II. The effect of promoter structure on selectivity
作者:Scott E. Denmark、Beritte L. Christenson、Stephen P. O'Connor
DOI:10.1016/0040-4039(95)00259-f
日期:1995.3
The catalytic, enantioselective cyclopropanation of cinnamyl alcohol has been accomplished with bis(iodomethyl)zinc in the presence of chiral bis(sulfonamides) derived from cyclohexanediamine. An extensive survey of diamine and sulfonamide structure has revealed a marked sensitivity to the spatial relationship of the amine groups, but only a modest dependence on the sulfonamide residue.
YOSHIOKA, MASATO;KAWAKITA, TAKASHI;OHNO, MASAJI, TETRAHEDRON LETT., 30,(1989) N3, C. 1657-1660