Synthesis, resolution and applications of 3,3′-bis(RO)-MeO-BIPHEP derivatives
摘要:
A series of optically pure 3,3'-bis(RO)-MeO-BIPHEP derivatives are prepared and used in palladium catalyzed asymmetric transformations. The phosphine oxide of (+/-)-5 is prepared in four steps from p-methoxyphenol and resolved using the novel resolving reagent chloro((L)-menthoxy)dimethylsilane. Subsequent conversions provide catalysts 8 and 9. Ligands 6, 7 and 10 are prepared in six steps from p-methoxyphenol and the phosphine oxides of 6 and 7, and 10 are resolved using di-p-toluoyl- and dibenzoyl-(L)-tartaric acid, respectively. (R)-3,3'-Bispivalate 8 is superior to the other catalysts in asymmetric Heck reaction with 2,3-dihydrofuran while (R)-(+)-bis(tolyloxy) 10 and (+)-(R)-sugar derivative 9 are better in the Pd-catalyzed polyene cyclization; however, the absolute sense of chirality in the product from the polyene cyclization was reversed to that obtained when (R)-(+)BINAP and (R)-(+)-MeO-BIPHEP were used. (C) 2004 Elsevier Ltd. All rights reserved.
A scalable electrochemical dehydrogenative cross-coupling of P(O)H compounds with RSH/ROH
作者:Yujun Li、Qi Yang、Liquan Yang、Ning Lei、Ke Zheng
DOI:10.1039/c9cc01378d
日期:——
A practical, scalable electrochemical dehydrogenative cross-coupling of P(O)H compounds with thiols, phenols and alcohols in both an undivided cell and a continuous-flow setup is disclosed. Its broad substrate scope (>50 examples), good functional-group tolerance and scalability (>10 g) show potential for practical synthesis. A preliminary mechanistic study suggests that the phosphorus radicals are
-promoted protocol for the selective and controllable esterification of P(O)OH compounds using O-nucleophiles (alcohols and phenols) as efficient esterification reagents is described. This method features a high efficiency and good functional-group tolerance, meaning a simple way to synthesize a broad spectrum of phosphinic and phosphoric acid esters from basic starting materials with moderate to excellent
Chloroform-based Atherton–Todd-type reactions of alcohols and thiols with secondary phosphine oxides generating phosphinothioates and phosphinates
作者:Shan Li、Tieqiao Chen、Yuta Saga、Li-Biao Han
DOI:10.1039/c5ra16015d
日期:——
Various valuable phosphinothioates and phosphinates including those with functional groups are readily prepared under mild reaction conditions via chloroform-based Atherton–Todd-type reactions of secondary phosphine oxides with alcohols and thiols, respectively.
Metal-free electrophilic phosphination of electron-rich arenes, arenols and aromatic thiols with diarylphosphine oxides
作者:Tao Yuan、Shenlin Huang、Chun Cai、Guo-ping Lu
DOI:10.1039/c7ob02620j
日期:——
phosphination of arenes, arenols and thiols has been disclosed. This chemistry, in which diaryl(((trifluoromethyl)sulfonyl)oxy)phosphines as a kind of electrophilic phosphination reagents are in situ generated from diarylphosphine oxides, provides an efficient and mild approach for the synthesis of aromatic organophosphorus compounds.