[Cu]-Catalyzed Domino Sonogashira Coupling Followed by Intramolecular 5-exo-dig Cyclization: Synthesis of 1,3-Dihydro-2-benzofurans
摘要:
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 [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.
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.