描述了一种新的合成方法,用于合成带有四个(A 4,顺式-A 2 B 2,顺式-ABC 2,反式-A 2 B 2)或更少(A,顺式-AB,顺式-A 2,反式- A 2)内消旋取代基。该方法需要在金属盐(MgBr 2,3摩尔当量)和非配位碱(DBU,10摩尔当量)在非配位溶剂(甲苯)中加热(常规或微波辐射)并暴露于空气中。反式-A 2 B 2-或反式-A 2-卟啉的合理合成是通过两个相同的1-酰基二吡咯甲烷的缩合反应实现的。各种内消旋的统计综合通过两个不相同的1-酰基吡咯烷甲烷的缩合获得取代的卟啉。两种途径都具有吸引人的特征,包括(1)无加扰;(2)高浓度(100 mM)的大环形成步骤中的高收率(最高60%);(3)合理的范围(芳基,杂芳基,烷基或无取代基),(4)微波辐射反应时间短(〜2 h),(5)容易进行脱金属的卟啉镁产物和(6)色谱纯化简便。统计途径的主要优点是获得了顺式取代的卟啉,而没有相应的反式异构体。例如,A
Acyl radicals are invaluable intermediates in organic synthesis, however their generation remains challenging. Herein, we present an unprecedented light‐driven, cobalt‐catalysed method for the generation of acyl radicals from readily available 2‐S‐pyridyl thioesters. The synthetic potential of this methodology was demonstrated in the Giese‐type acylation of activated olefins in the presence of heptamethyl
Direct Synthesis of Palladium Porphyrins from Acyldipyrromethanes
作者:Duddu S. Sharada、Ana Z. Muresan、Kannan Muthukumaran、Jonathan S. Lindsey
DOI:10.1021/jo050120v
日期:2005.4.1
multistep synthesis which requires a 2e- + 2H+ reduction per each 1-acyldipyrromethane (4e- + 4H+ overall) followed by a 6e- + 6H+ oxidation. The analogous reaction of a 1,9-diacyldipyrromethane and a dipyrromethane also gives the palladium porphyrin. Seven palladium porphyrins have been prepared in yields of 25−57%. The direct route also can be used with Cu(OAc)2·H2O to give the copper porphyrin albeit
The present invention provides compounds having the general structure A, or a pharmaceutically acceptable derivatives thereof:
wherein R is an alkyl group, and R
1
comprises at least one moiety selected from a group consisting of an alkyl, an alkenyl, an aryl, a heterocycle, hydroxyl, ester, amido, aldehyde, and a halogen.
Diastereoselective aldol condensation of silyl ketene acetal of 2-pyridyl thioester with benzaldehyde
作者:Kwee-Hyun Suh、Dong-Joon Choo
DOI:10.1016/0040-4039(95)01231-6
日期:1995.8
The TiCl4-mediated aldol reaction of the (E)-O-silyl ketene-O,S-acetal derived from 2-pyridyl thioester with benzaldehyde gave exclusively syn-aldol product. In contrast, BF3-mediated reaction afforded the corresponding anti-isomer as a major product. Chelation and acyclic transition state are postulated in order to explain the observed selectivities.
REDUCTIVE COUPLING OF<i>S</i>-(2-PYRIDYL) ALIPHATIC THIOATES BY USE OF BIS(1,5-CYCLOOCTADIENE)NICKEL
作者:Makoto Onaka、Yoshio Matsuoka、Teruaki Mukaiyama
DOI:10.1246/cl.1980.905
日期:1980.8.5
S-(2-Pyridyl) aliphatic thioates are reductively dimerized to give α-diketones and α-hydroxy ketones on treatment with bis(1,5-cyclooctadiene)nickel at 40°C.