Intramolecular Cyclopropanation of Unsaturated Terminal Epoxides and Chlorohydrins
作者:David M. Hodgson、Ying Kit Chung、Irene Nuzzo、Glòria Freixas、Krystyna K. Kulikiewicz、Ed Cleator、Jean-Marc Paris
DOI:10.1021/ja0672932
日期:2007.4.1
Lithium 2,2,6,6-tetramethylpiperidide (LTMP)-induced intramolecular cyclopropanation of unsaturated terminal epoxides provides an efficient and completely stereoselective entry to bicyclo[3.1.0]hexan-2-ols and bicyclo[4.1.0]heptan-2-ols. Further elaboration of C-5 and C-6 stannyl-substituted bicyclo[3.1.0]hexan-2-ols via Sn-Li exchange/electrophile trapping or Stille coupling generates a range of substituted
作者:Papapida Pornsuriyasak、Sneha C. Ranade、Aixiao Li、M. Cristina Parlato、Charles R. Sims、Olga V. Shulga、Keith J. Stine、Alexei V. Demchenko
DOI:10.1039/b817684a
日期:——
A new surface-tethered iterative carbohydrate synthesis (STICS) technology is presented in which a surface functionalized ‘stick’ made of chemically stable high surface area porous gold allows one to perform cost efficient and simple synthesis of oligosaccharide chains; at the end of the synthesis, the oligosaccharide can be cleaved off and the stick reused for subsequent syntheses.
7-Ethynyl-2,4,9-Trithiaadamantane and Related Methods
申请人:Hu Jun
公开号:US20080177094A1
公开(公告)日:2008-07-24
7-ethynyl-2,4,9-trithiaadamantane and related methods are presented. Manufacturing 7-ethynyl-2,4,9-trithiaadamantane includes the steps of: (1) reducing alkyl 2,4,9-trithiaadamantane-7-carboxylate to produce 7-hydroxymethyl-2,4,9-trithiaadamantane; (2) oxidizing 7-hydroxymethyl-2,4,9-trithiaadamantane to produces 7M carbonyl-2,4,9-trithiaadamantane; and (3) reacting 7-carbonyl-2,4,9-trithiaadamantane with Ohira-Bestmann reagent to produces 7-ethynyl-2,4,9-trithiaadamantane. Molecular wires having 2,4,9-trithiaadamantane surface anchors are also disclosed.
7-ETHYNYL-2,4,9-TRITHIAADAMANTANE AND RELATED METHODS
申请人:Hu Jun
公开号:US20100072425A1
公开(公告)日:2010-03-25
7-ethynyl-2,4,9-trithiaadamantane and related methods are presented. Manufacturing 7-ethynyl-2,4,9-trithiaadamantane includes the steps of: (1) reducing alkyl 2,4,9-trithiaadamantane-7-carboxylate to produce 7-hydroxymethyl-2,4,9-trithiaadamantane; (2) oxidizing 7-hydroxymethyl-2,4,9-trithiaadamantane to produces 7-carbonyl-2,4,9-trithiaadamantane; and (3) reacting 7-carbonyl-2,4,9-trithiaadamantane with Ohira-Bestmann reagent to produces 7-ethynyl-2,4,9-trithiaadamantane. Molecular wires having 2,4,9-trithiaadamantane surface anchors are also disclosed.
We prepared two new linkers, S-functionalized adamantane derivatives 2 and 3, which bind as monolayers on polycrystalline gold. From these surface anchors, both L- and D-isomers of alanine can be grown as thin films of a-helical polypeptides directed from the gold surface by using the appropriate N-carboxyalanine anhydride. FT-IR Studies show that these layers are roughly 1000-Angstrom thick and that, under the same growth conditions. the L-polypeptide layers grow at a rate ca. 30% greater than that of the non-natural D-amino acid. X-Ray photoelectron spectroscopy studies shove that, upon equilibration, all three S-atoms of the sulfide moieties of 2 are bound to the gold surface, and that, on average, three of the four thiols of 3 are chemoadsorbed. The essential role of H2O on the surface of these films as a necessary component in these gas-phase polymerization reactions is demonstrated.