Highly efficient catalytic dehydrative S-allylation of thiols and thioic S-acids
作者:Shinji Tanaka、Prasun Kanti Pradhan、Yusuke Maegawa、Masato Kitamura
DOI:10.1039/c0cc00096e
日期:——
A SH-selective allylation method using [CpRu(2-quinolinecarboxylato)(η3-C3H5)]PF6 has been realized in various solvents including aqueous media to give allyl sulfides and allyl S-thioates, demonstrating the potential applicability to lipopeptide chemistry.
One-pot synthesis of thioesters with sodium thiosulfate as a sulfur surrogate under transition metal-free conditions
作者:Yen-Sen Liao、Chien-Fu Liang
DOI:10.1039/c8ob00178b
日期:——
In this paper, we report an efficient synthetic method for thioester formation fromsodium thiosulfate pentahydrate, organic halides, and aryl anhydrides. In the one-pot two-step reactions developed in this study, sodium thiosulfate was used as the sulfur surrogate for acylation with anhydrides, followed by substitution with organic halides through the in situ generation of thioaroylate. Furthermore
coupling of readily available aroylhydrazides with disulfides is developed, in which oxidative expulsion of N2 overcomes the activation barrier between the carboxylic acidderivatives and the products. The reaction produces various thioesters in good to excellent yields with good functional group tolerance. In the reaction, stable and easily available aroylhydrazides are used as acyl sources and the
通过易得的芳酰肼与二硫化物的铜催化的氧化偶联,开发了另一种硫酯化反应,其中N 2的氧化排出克服了羧酸衍生物和产物之间的活化障碍。该反应以良好的收率和优异的官能度耐受性产生了各种硫酯。在该反应中,将稳定且容易获得的芳酰基酰肼用作酰基源,并将相对无味的二硫化物用作S源。机理研究表明,铜盐与氧化剂(NH 4)2 S 2 O 8的反应 可以实现串联过程,包括去质子化,自由基介导的脱氮和CS键形成。
The application of a mechanistic model leads to the extension of the Sharpless asymmetric dihydroxylation to allylic 4-methoxybenzoates and conformationally related amine and homoallylic alcohol derivatives.
作者:E. J. Corey、Angel Guzman-Perez、Mark C. Noe
DOI:10.1021/ja00149a003
日期:1995.11
The scope and utility of the Sharpless asymmetric dihydroxylation has been expanded to include the use of allylic 4-methoxybenzoates as precursors of a wide variety of substituted chiral glycerol derivatives. The allylic 4-methoxybenzoyl group was found to be superior to other allylic alcohol protecting groups with respect to both yield and enantiomeric purity of the product. For example, asymmetric dihydroxylation of allyl 4-methoxybenzoate (6a) using the (DHQD)(2)PYDZ . OsO4 (1 . OsO4) catalyst system affords (S)-3-(4-methoxybenzoyloxy)-1,2-propanediol (7a) in >99% yield and 98% ee. The 4-methoxybenzoates of a variety of other allylic alcohols also serve as excellent substrates, in contrast to the parent alcohols themselves. The efficient asymmetric dihydroxylation of homoallylic 4-methoxyphenyl ethers (12a and 15), allyl 9-fluorenimine (18b), bis(homoallyl) 4-methoxybenzoate (14) and other structurally related substrates is also described. This methodology was developed under mechanistic guidance from the transition state model advanced earlier by us for the bis-cinchona alkaloid catalyzed asymmetric dihydroxylation reaction. The 4-methoxybenzoyl group functions not only to selectively protect one of the hydroxy groups of the product triol for subsequent synthetic manipulation but also to provide an extended binding group that participates in hydrophobic and aryl-aryl interactions with the U-shaped binding pocket of the (DHQD)(2)PYDZ . OsO4 catalyst (1 . OsO4), thereby enhancing enantioselectivity.