Regioselective Quinazolinone-Directed Ortho Lithiation of Quinazolinoylquinoline: Practical Synthesis of Naturally Occurring Human DNA Topoisomerase I Poison Luotonin A and Luotonins B and E
摘要:
A regioselective quinazolinone-directed ortho lithiation on an adjacent quinoline moiety has been used as a key step for a short, efficient, and practical synthesis of the human DNA topoisomerase I poison luotonin A and luotonins B and E. The quinazolinoylquinoline 5 on treatment with in situ-generated nonnucleophilic mesityllithium furnished the desired dilithiated intermediate 6, which on treatment with formaldehyde followed by Mitsunobu ring closure reaction gave luotonin A (1a) in very good yield. The reaction of dilithiated intermediate 6 with DMF directly furnished luotonin B (1b) in 81% yield. Luotonin B (1b) on methylation with p-TSA/methanol gave luotonin E (1c) in 82% yield.
我们介绍了在氢氧化钾和[Ir(2-PyCH 2(C 4 H 5 N 2))(COD)] OTf(1)或[Ir(2-PyCH 2 PBu 2 t)(COD)] OTf(2)。该方法以高收率和优异的官能团耐受性提供脂族和苄基羧酸盐。我们举例说明了该方法在各种伯醇中的应用,包括涉及杂环甚至是游离胺的伯醇。复杂2与醇反应以形成晶体学表征催化中间体[IRH(η 1,η 3 -C 8 ħ 12)(2-PyCH 2 P吨卜2)](2A)和物[Ir 2 ħ 3(CO)(2- PyCH 2 P t Bu 2){μ-(C 5 H 3 N)CH 2 P t Bu 2 }](2c)。反应性1和2的意外相似之处在此反应中,以及对几种铱中间体的合成研究,使我们能够形成催化剂活化机理的一般建议,该催化剂分别控制甘油和甲酸脱氢反应中1和2的不同反应性。此外,仔细分析氧化顺序中的有机中间体,可以使人们对蒂申科和坎尼扎罗反应在整个氧化反应中的作用有了新的认识。
Development of a palladium-catalyzed decarboxylative cross-coupling of (2-azaaryl)carboxylates with aryl halides
作者:Christopher K. Haley、Christopher D. Gilmore、Brian M. Stoltz
DOI:10.1016/j.tet.2013.03.085
日期:2013.7
A catalytic method for the decarboxylative coupling of 2-(azaaryl)carboxylates with aryl halides is described. The decarboxylativecross-coupling presented is mediated by a system catalytic in both palladium and copper without requiring stoichiometric amounts of organometallic reagents or organoboronic acids. This method circumvents additional synthetic steps required to prepare 2-azaaryl organometallics
Synthesis of Aryl Ethers from Benzoates through Carboxylate-Directed CH-Activating Alkoxylation with Concomitant Protodecarboxylation
作者:Sukalyan Bhadra、Wojciech I. Dzik、Lukas J. Gooßen
DOI:10.1002/anie.201208755
日期:2013.3.4
copper/silver bimetallic catalyst system, aromatic carboxylate salts undergo ortho CH alkoxylation with concomitant loss of the carboxylate directing group in a protodecarboxylation step (see scheme, FG=functional group). This process provides a convenient synthetic access to the important class of aromatic ethersfrom widely available carboxylic acids.
Iridium Catalysts for Acceptorless Dehydrogenation of Alcohols to Carboxylic Acids: Scope and Mechanism
作者:Valeriy Cherepakhin、Travis J. Williams
DOI:10.1021/acscatal.8b00105
日期:2018.5.4
η3-C8H12)(2-PyCH2PtBu2)] (2a) and [Ir2H3(CO)(2-PyCH2PtBu2)μ-(C5H3N)CH2PtBu2}] (2c). The unexpected similarities in reactivities of 1 and 2 in this reaction, along with synthetic studies on several of our iridium intermediates, enable us to form a general proposal of the mechanisms of catalyst activation that govern the disparate reactivities of 1 and 2, respectively, in glycerol and formic acid dehydrogenation
我们介绍了在氢氧化钾和[Ir(2-PyCH 2(C 4 H 5 N 2))(COD)] OTf(1)或[Ir(2-PyCH 2 PBu 2 t)(COD)] OTf(2)。该方法以高收率和优异的官能团耐受性提供脂族和苄基羧酸盐。我们举例说明了该方法在各种伯醇中的应用,包括涉及杂环甚至是游离胺的伯醇。复杂2与醇反应以形成晶体学表征催化中间体[IRH(η 1,η 3 -C 8 ħ 12)(2-PyCH 2 P吨卜2)](2A)和物[Ir 2 ħ 3(CO)(2- PyCH 2 P t Bu 2)μ-(C 5 H 3 N)CH 2 P t Bu 2 }](2c)。反应性1和2的意外相似之处在此反应中,以及对几种铱中间体的合成研究,使我们能够形成催化剂活化机理的一般建议,该催化剂分别控制甘油和甲酸脱氢反应中1和2的不同反应性。此外,仔细分析氧化顺序中的有机中间体,可以使人们对蒂申科和坎尼扎罗反应在整个氧化反应中的作用有了新的认识。