Asymmetric synthesis of benzofuryl β-amino alcohols by the transfer hydrogenation of α-functionalized ketones
作者:Agnieszka Tafelska-Kaczmarek、Marek P. Krzemiński、Marta Ćwiklińska
DOI:10.1016/j.tet.2017.05.059
日期:2017.7
The asymmetrictransferhydrogenation of representative benzofuryl α-sulfonyloxy ketones and N-protected α-amino ketones with an azeotropic mixture of formic acid/triethylamine, catalyzed by RhCl[(R,R)-TsDPEN](C5Me5), afforded the corresponding 1,2-diol monosulfonates and N-substituted β-amino alcohols in high yields and with enantioselectivities up to 99%. Transformation of the reduction products
用RhCl [(R,R)-TsDPEN](C 5 Me 5)催化的甲酸/三乙胺共沸混合物将代表性的苯并呋喃基α-磺酰氧基酮和N-保护的α-氨基酮进行不对称转移氢化,得到了相应的1,2-二醇单磺酸盐和N-取代的β-氨基醇,收率高,对映选择性高达99%。还描述了还原产物向具有伯胺基的手性苯并呋喃基β-氨基醇的转化。
Hypervalent Iodine(III)-Mediated Tosyloxylation of 4-Hydroxycoumarins
作者:Bowen Xu、Yiping Gao、Jianwei Han、Zejing Xing、Sihan Zhao、Ziyang Zhang、Runlin Ren、Limin Wang
DOI:10.1021/acs.joc.9b01323
日期:2019.8.16
An efficient approach was developed for synthesis of 3-tosyloxy-4-hydroxycoumarins under mild conditions by using Koser’s reagents. The reaction tolerated various functional groups, and the products served as useful aromatic building blocks. Additionally, a plausible mechanism via iodonium ylide was proposed, and the oral anticoagulant Warfarin was synthesized in good yield.
simple approach for palladium-catalyzed C–H functionalization reactions utilizing an organophosphorus/sulfonate hypervalent iodine reagent as both an oxidant and the source of a functional group has been developed. Through this method, the oxidative phosphorylation-, sulfonation-, and hydroxylation of unactivated benzyl C(sp3)–H bonds, along with the hydroxylation and arylation of aryl C(sp2)–H bonds,
Room temperature iron(<scp>ii</scp>)-catalyzed radical cyclization of unsaturated oximes with hypervalent iodine reagents
作者:Shichao Yang、Hongji Li、Pinhua Li、Jingya Yang、Lei Wang
DOI:10.1039/c9ob02424g
日期:——
Here, we disclose an iron(ii)-catalyzed I-O bond cleavage of Koser's hypervalent iodine reagents (HIRs) that initiated the radical cyclization of unsaturated oximes at room temperature. This strategy is successfully applied for the construction of the isoxazoline backbone in an efficient manner. In particular, the direct introduction of a TsO group into products facilitates their late-stage transformations
We report a regioselective remote difunctionalization of unreactive C–H bonds of 2H-indazoles with Koser's reagents to provide C-4,7 substituted 2H-indazole derivatives.