and trifluoroethanol (TFE) through product studies and transient absorption spectroscopy. Chloride loss from triplet 6 gave triplet hydroxyphenyl cation 14, which equilibrated with triplet oxocyclohexadienylydene 15 within a few tens of nanoseconds; the cation can, however, be selectively trapped by allyltrimethylsilane (k(ad) = 10(8)-10(9) m(-1) s(-1)) to give a phenonium ion and the allylated phenol
Ion triggered alkylation of biological targets by silyloxy aromatic
申请人:The Research Foundation of State University of New York
公开号:US05493012A1
公开(公告)日:1996-02-20
A silyloxy aromatic derivative capable of alkylating a target biological molecule when activated by ionic strength. A sequence directed reagent may be constructed by conjugating a methyl silyloxy aromatic derivative to a hexamethyiamino linker attached to either the 5' or 3' terminus of an oligonucleotide. Annealing this modified fragment of DNA to its complementary sequence allows for target modification subsequent to ionic activation. The product of this reaction is a covalent crosslink between the reagent and target strands resulting from an alkylation of DNA by the activated silyloxy aromatic derivative. In a preferred embodiment, a nitrophenyl or bromo group is attached to a methyl group of the silyloxy aromatic derivative. This reagent may be similarly linked to an oligonucleotide probe. Activation of the alkylating agent by an ionic signal (X) which may naturally occur, or may be introduced into the media containing the target molecule, such as by the introduction of a salt (MX).
Synthesis of Oxygen- and Sulfur-Bridged Dirhodium Complexes and Their Use As Catalysts in the Chemoselective Hydrogenation of Alkenes
作者:Chuan Zhu、Noriaki Yukimura、Motoki Yamane
DOI:10.1021/om100067r
日期:2010.5.10
Oxygen-bridged and sulfur-bridged rhodium homobimetallic complexes were synthesized as airstable crystals by using 2,6-bis(phosphanylmethyl)phenolate and -thiophenolate as the ligands, respectively. The oxygen-bridged dirhodium complex has a symmetrical structure where the carbon atom at the ipso position, oxygen, and two rhodium atoms are located in the same plane. It is thermally stable compared to the sulfur-bridged dirhodium complex and shows catalytic activity for hydrogenation of alkenes with high chemoselectivity.
Regioselective lithiation/retro-Brook rearrangement via direct deprotonation
作者:Yongping He、Haitao Hu、Xingang Xie、Xuegong She
DOI:10.1016/j.tet.2012.11.024
日期:2013.1
A regioselective lithiation/retro-Brook rearrangement via direct deprotonation was developed. Varieties of benzyl silanes and vinyl silanes are obtained effectively up to 93% yields. (c) 2012 Elsevier Ltd. All rights reserved.