146758-90-9Relevant academic research and scientific papers
Catalytic carbometalation/cross-coupling sequence across alkynyl(2-pyridyl)silanes leading to a diversity-oriented synthesis of tamoxifen-type tetrasubstituted olefins
Kamei, Toshiyuki,Itami, Kenichiro,Yoshida, Jun-Ichi
, p. 1824 - 1835 (2007/10/03)
A general synthetic scheme for tamoxifen-type tetrasubstituted olefins based on the novel Cu-catalyzed carbomagnesation across alkynyl(2-pyridyl)silane has been developed. A wide array of electronically and structurally diverse tetrasubstituted olefins can be prepared in a regiocontrolled, stereo-controlled, and diversity-oriented manner. Noteworthy features are that (i) the three aryl groups, which are believed to be important (essential) for anti-estrogenic activity, can be varied at will because they all stem from readily available aryl iodides, and (ii) any stereo- and regioisomers can, in principle, be prepared by simply changing the order use of the aryl iodides in the sequence.
The Ireland-Claisen rearrangement as a probe for the diastereoselectivity of nucleophilic attack on a double bond adjacent to a stereogenic centre carrying a silyl group
Betson, Mark S.,Fleming, Ian
, p. 4005 - 4016 (2007/10/03)
The E- and Z-silyl enol ethers 4 derived from allyl 3-R-3-dimethyl(phenyl)silylpropanoate (R = Me, Pri and Ph) and the Z-silyl enol ethers 7 derived from 4-R-4-dimethyl(phenyl)silylbut-2-enyl acetate (R = Me and Pri) undergo Ireland-
Diversity-Oriented Synthesis of Tamoxifen-type Tetrasubstituted Olefins
Itami, Kenichiro,Kamei, Toshiyuki,Yoshida, Jun-Ichi
, p. 14670 - 14671 (2007/10/03)
A general synthetic scheme for tamoxifen-type tetrasubstituted olefins based on the novel Cu-catalyzed carbomagnesation across alkynyl(2-pyridyl)silane has been developed. A wide array of electronically and structurally diverse tetrasubstituted olefins can be prepared in a regiocontrolled, stereocontrolled, and diversity-oriented manner. Noteworthy features are that (i) the three aryl groups, which are believed to be important (essential) for anti-estrogenic activity, can be varied at will because they all stem from readily available aryl iodides, and (ii) any stereo- and regioisomers can, in principle, be prepared by simply changing the applying order of aryl iodides into the sequence. Copyright
A synthesis of enantiomerically enriched propargyl silanes
Fleming, Ian,Mwaniki, Joseph M.
, p. 1237 - 1247 (2007/10/03)
Reduction of ethyl 3-methyl-, 3-isopropyl- and 3-n-pentyl-3-[dimethyl(phenyl)silyl]propanoates 4 with DIBAL to the aldehydes 5, enol trifluoromethanesulfonate (triflate) formation using trifluoromethanesulfonic (triflic) anhydride and 2,6-di-tert-butylpyridine, and elimination using LDA, gives the propargyl silanes 8. The esters 4 could also be prepared enantiomerically enriched (11), and the final products are the enantiomerically enriched propargyl (homochiral) silanes 14.
The stereochemistry of the vinylogous Peterson elimination
Fleming, Ian,Morgan, Ian T.,Sarkar, Achintya K.
, p. 2749 - 2763 (2007/10/03)
Base-induced eliminations of the vinylogous β-hydroxysilanes 7, 9, 11 and 12 are stereospecifically syn, giving largely the trans,trans-diene 8 from 7 and 11, the cis,trans-diene 10 from 9, and the trans,cis-diene 13 from 12. When a cis double bond is produced, it is selectively placed adjacent to the carbon atom that originally carried the hydroxy group. E2′ Reactions with silyl as the electrofugal group and acetate as the nucleofugal group, initiated by fluoride ion, are not stereospecific, but can be highly stereoselective in favour of the trans,trans-diene 8 when the carbon substituent at the silicon-bearing end is a cyclohexyl group and the double bond is cis, and in favour of the trans,cis-diene 13 when the carbon substituent at the silicon-bearing end is a methyl group and the double bond is trans. Attempts to use the Peterson reactions to make o-quinodimethanes stereospecifically failed, with no evidence of 1,4-elimination from the alcohols 40 and 41. The corresponding E2′ reaction from the esters using fluoride ion on the acetates or formates 46 and 47 gave stereoselectively the E,E-quinodimethane 48.
The Regiochemistry and Stereochemistry of the Hydroboration of Allylsilanes
Fleming, Ian,Lawrence, Nicholas J.
, p. 3309 - 3326 (2007/10/02)
The hydroboration of a wide range of allylsilanes 3 and 5-21 is found to be generally regioselective for attachment of the boron to C-3 and hydrogen to C-2 of the allyl unit, and to be generally stereoselective in the sense 1, with attachment of the boron
