Efficient Method for the Preparation of Carboxylic Acid Alkyl Esters or Alkyl Phenyl Ethers by a New-Type of Oxidation–Reduction Condensation Using 2,6-Dimethyl-1,4-benzoquinone and Alkoxydiphenylphosphines
A new-type of oxidation–reduction condensation proceeded smoothly to afford carboxylic acid alkyl esters or alkyl phenyl ethers in good to high yields by combined use of alkoxydiphenylphosphines (1...
一种新型氧化还原缩合反应顺利进行,通过结合使用烷氧基二苯基膦(1...
New Method for the Preparation of Carboxylic Esters
Various carboxylic esters including functionalized ones are prepared in good yields from equimolar amounts of free carboxylic acids and alcohols under mild conditions by the use of 2-chloro- or 2-bromopyridinium salt, a new and efficient coupling reagent.
作者:Steven V. Ley、Miles N. Tackett、Matthew L. Maddess、James C. Anderson、Paul E. Brennan、Michael W. Cappi、Jag P. Heer、Céline Helgen、Masakuni Kori、Cyrille Kouklovsky、Stephen P. Marsden、Joanne Norman、David P. Osborn、María Á. Palomero、John B. J. Pavey、Catherine Pinel、Lesley A. Robinson、Jürgen Schnaubelt、James S. Scott、Christopher D. Spilling、Hidenori Watanabe、Kieron E. Wesson、Michael C. Willis
DOI:10.1002/chem.200801656
日期:2009.3.9
Rapamycin (1) is a macrocyclic natural product, established as a potent immunosuppressant and currently of interest to the scientific community as the framework for a series of novel anticancer drugs. Extensive studies have culminated in a new convergent totalsynthesis of 1, which features a number of group‐derived methodologies and an unusual catechol‐templating strategy for the construction of the
Ceric ammonium nitrate (CAN)—a useful catalyst for the rapid and high-yield esterification of carboxylic acids and alcohols with special reference to steroid and other multi-functional natural products
作者:Papori Goswami、Pritish Chowdhury
DOI:10.1039/b005908k
日期:——
Ceric ammoniumnitrate (CAN) acts as a versatile catalyst for the esterification of carboxylicacids and alcohols, including steroids and other multi-functional natural products, in excellent yields under mild and convenient reaction conditions.
α-dihalogeno β-hydroxy esters or amides by using commercially available Noyori’s complex [RuCl(p-cymene)(R,R)-TsDPEN] as a catalyst (S/C = 100−200) in the asymmetrictransferhydrogenation of the corresponding ketones. Moderate to high yields (up to 99%) and excellent enantioselectivities (up to >99% ee) were achieved for a series of variously substituted dichloro and difluoro β-hydroxy esters and amides.
通过使用市售的Noyori配合物[RuCl(p- Cymene)(R,R)-TsDPEN]作为催化剂(S / C = 100-200)在相应的酮的不对称转移氢化中。对于一系列不同取代的二氯和二氟β-羟基酯和酰胺,可实现中等至高收率(高达99%)和出色的对映选择性(高达> 99%ee)。