The first example of formylation of allylzinc reagents using S-phenyl thioformate is presented. The reaction proceeded undermildconditions without any transition-metal catalyst, forming quaternarycarboncenters with reactive functionalities, such as formyl and vinyl groups. Moreover, Barbier-type formylation of an allylic bromide with a sterically demanding thioformate was achieved. As a preliminary
A Rh-catalyzed 1,2-sulfur migration/aza-Diels–Alder cascade initiated by aza-vinyl carbenoids from sulfur-tethered N-sulfonyl-1,2,3-triazoles
作者:Yu Jiang、Xiang-Ying Tang、Min Shi
DOI:10.1039/c4cc08829h
日期:——
A novel Rh(ii) catalyzed intramolecular 1,2-sulfur migration/intermolecular aza-Diels–Alder cascade of sulfur-tetheredN-sulfonyl-1,2,3-triazoles has been developed, efficiently affording sulfur-containing tetrahydropyridine derivatives.
Stereoselective Synthesis of δ-Lactones from 5-Oxoalkanals via One-Pot Sequential Acetalization, Tishchenko Reaction, and Lactonization by Cooperative Catalysis of Samarium Ion and Mercaptan
作者:Jue-Liang Hsu、Jim-Min Fang
DOI:10.1021/jo016058t
日期:2001.12.1
sequence of acetalization, Tishchenko reaction and lactonization. The deliberative use of mercaptan, by comparison with alcohol, is advantageous to facilitate the catalytic cycle. The reaction mechanism and stereochemistry are proposed and supported by some experimental evidence. Such samarium ion/mercaptan cocatalyzed reactions show the feature of remote control, which is applicable to the asymmetric synthesis
13C NMR as a general tool for the assignment of absolute configuration
作者:Iria Louzao、José Manuel Seco、Emilio Quiñoá、Ricardo Riguera
DOI:10.1039/c0cc02774j
日期:——
(13)C NMR, alone or in combination with (1)H NMR, allows the assignment of the absolute configuration of chiral alcohols, amines, carboxylic acids, thiols, cyanohydrins, sec,sec-diols and sec,sec-aminoalcohols, derivatized with appropriate chiral auxiliaries. This extends the assignment possibilities of NMR to fully deuterated and to nonproton containing compounds.
Chiral Thiols: The Assignment of Their Absolute Configuration by <sup>1</sup>H NMR
作者:Silvia Porto、José Manuel Seco、Aurelio Ortiz、Emilio Quiñoá、Ricardo Riguera
DOI:10.1021/ol7022196
日期:2007.11.1
A general NMR spectroscopy protocol for determination of absoluteconfiguration of thiols, that includes the introduction of new aryl-tert-butoxyacetic acids as chiral derivatizing agents (CDAs), is described.