多米诺钯催化双O-H键活化形成C-C和C-O键:合成6,6-二烷基-6 H-苯并[ c ]苯并二甲基苯
摘要:
提出了α,α-二烷基-(2-溴芳基)甲醇有效的钯催化多米诺反应为6,6-二烷基-6 H-苯并[ c ]色烯的反应。它们的形成可以通过一个五元的Pd(II)循环来解释,该循环有效地涉及与第二个分子的多米诺骨牌同质偶联,β碳裂解以及最后的分子内布赫瓦尔德-哈特维格环化。这种多米诺骨牌工艺实际上涉及打破五个σ键(2C–Br,2O–H和C–C)和形成两个新的σ键(CC和C–O)。这种机理途径是前所未有的,并进一步说明了过渡金属催化的作用。
多米诺钯催化双O-H键活化形成C-C和C-O键:合成6,6-二烷基-6 H-苯并[ c ]苯并二甲基苯
摘要:
提出了α,α-二烷基-(2-溴芳基)甲醇有效的钯催化多米诺反应为6,6-二烷基-6 H-苯并[ c ]色烯的反应。它们的形成可以通过一个五元的Pd(II)循环来解释,该循环有效地涉及与第二个分子的多米诺骨牌同质偶联,β碳裂解以及最后的分子内布赫瓦尔德-哈特维格环化。这种多米诺骨牌工艺实际上涉及打破五个σ键(2C–Br,2O–H和C–C)和形成两个新的σ键(CC和C–O)。这种机理途径是前所未有的,并进一步说明了过渡金属催化的作用。
Domino [Pd]-Catalysis: One-Pot Synthesis of Isobenzofuran-1(3<i>H</i>)-ones
作者:Lodi Mahendar、Gedu Satyanarayana
DOI:10.1021/acs.joc.6b01396
日期:2016.9.2
An efficient domino [Pd]-catalysis for the synthesis of isobenzofuran-1(3H)-ones is presented. The strategy shows broad substrate scope and is amenable to o-bromobenzyl tertiary/secondary/primary alcohols. Significantly, the method was applied to the synthesis of antiplatelet drug n-butyl phthalide and cytotoxic agonist 3a-[4′-methoxylbenzyl]-5,7-dimethoxyphthalide.
A Sequential Pd/Norbornene-Catalyzed Process Generates <i>o-</i>Biaryl Carbaldehydes or Ketones via a Redox Reaction or 6<i>H</i>-Dibenzopyrans by C–O Ring Closure
作者:Elena Motti、Nicola Della Ca’、Di Xu、Anna Piersimoni、Elena Bedogni、Zhi-Ming Zhou、Marta Catellani
DOI:10.1021/ol302889t
日期:2012.11.16
o-Biaryl carbaldeydes and ketones are obtained through the one-pot reaction of o-aryl iodides with o-bromobenzyl alcohols under the catalytic action of Pd and norbornene, in the presence of a base. The same reaction can also give dibenzopyrans by Pd and norbornene catalysis with a different termination, leading to C-O ring closure. In both cases the process first leads to a five-membered palladacycle, which controls C-C coupling, then to a seven-membered oxapalladacycle, which gives aldehydes and ketones or dibenzopyrans.
[Cu]-Catalyzed Domino Sonogashira Coupling Followed by Intramolecular 5-<i>exo</i>-<i>dig</i> Cyclization: Synthesis of 1,3-Dihydro-2-benzofurans
An efficient [Cu]-catalyzed domino Sonogashira coupling of o-bromobenzyl tertiary alcohols with terminal aryl acetylenes followed by an intramolecular anti-5-exo-dig cyclization is presented. The terminal aryl acetylenes were identified as ideal coupling partners that permit in situ intramolecular oxacyclization by the hydroxyl group as a pre-existing nucleophile of the alcohol. Notably, the intramolecular nucleophilic attack of the hydroxyl group took place on the alkyne moiety in a highly regio- and stereoselective manner. Interestingly, this method was amenable to a wide variety of o-bromobenzyl tertiary alcohols and furnished the corresponding cyclic ethers. On the other hand, when terminal alkyl acetylenes were used as the coupling partners, the reaction was impeded after the Sonogashira coupling.
Domino One-Pot Process for the Synthesis of Isobenzofuran-1(3<i>H</i>)-ones via [Cu]-Catalysis Using Water as the Green Solvent
作者:Lodi Mahendar、Gedu Satyanarayana
DOI:10.1021/acs.joc.5b00888
日期:2015.7.17
An efficient domino one-pot strategy via [Cu]-catalyzed intermolecular "cyanation" of o-bromobenzyl alcohols -> in situ intramolecular "nudeophilic attack" -> "hydrolysis" is presented, for the synthesis of isobenzofuran-1(3H)-ones. Significantly, the reaction is successfully carried out under environmentally benign conditions, using water as sole green solvent.
A Domino Palladium-Catalyzed C–C and C–O Bonds Formation via Dual O–H Bond Activation: Synthesis of 6,6-Dialkyl-6<i>H</i>-benzo[<i>c</i>]chromenes
An efficient Pd-catalyzed domino reaction of α,α-dialkyl-(2-bromoaryl)methanols to 6,6-dialkyl-6H-benzo[c]chromenes is presented. Their formation can be explained via a five membered Pd(II)-cycle that efficiently involves a domino homocoupling with the second molecule, β-carbon cleavage, and finally intramolecular Buchwald–Hartwig cyclization. This domino process effectively involves breaking of five
提出了α,α-二烷基-(2-溴芳基)甲醇有效的钯催化多米诺反应为6,6-二烷基-6 H-苯并[ c ]色烯的反应。它们的形成可以通过一个五元的Pd(II)循环来解释,该循环有效地涉及与第二个分子的多米诺骨牌同质偶联,β碳裂解以及最后的分子内布赫瓦尔德-哈特维格环化。这种多米诺骨牌工艺实际上涉及打破五个σ键(2C–Br,2O–H和C–C)和形成两个新的σ键(CC和C–O)。这种机理途径是前所未有的,并进一步说明了过渡金属催化的作用。