Cobalt-Catalyzed Enantioselective Intramolecular Hydroacylation of Ketones and Olefins
摘要:
Cobalt-chiral diphoshine catalytic systems promote intramolecular hydroacylation reactions of 2-acylbenzaldehydes and 2-alkenylbenzaldehydes to afford phthalide and indanone derivatives, respectively, in moderate to good yields with high enantioselectivities. The ketone hydroacylation did not exhibit a significant H/D kinetic isotope effect (KIE) with respect to the aldehyde C-H bond, indicating that C-H activation would not be involved in the rate-limiting step.
Synthesis of synthons: The asymmetric hydrogenation and subsequent in situ lactonization with Ru-diphosphines results in the direct conversion of a series of 2-acylarylcarboxylates including 2-aroylarylcarboxylates into the corresponding optically active 3-substituted phthalides under mild reaction conditions.
A nickel-catalyzed asymmetric Suzuki–Miyaura cross-coupling of racemic 3-bromo-phthalides and arylboronic acids was realized for the synthesis of diverse chiral 3-aryl-phthalides in moderate to excellent reaction yields. The reaction proceeded in a stereoconvergent manner and high enantioselectivities were observed for most examined examples. A number of functional groups like aldehyde, ester and bromide
A facile and convenient synthesis of the chiral phthalide framework catalyzed by cationic iridium was developed. The method utilized cationic iridium/bisphosphine‐catalyzed asymmetric intramolecular carbonyl hydroacylation of 2‐keto benzaldehydes to furnish the corresponding optically active phthalide products in good to excellent enantioselectivities (up to 98% ee ). The mechanistic studies using
Cascade Enantioselective Synthesis of 3-Arylphthalides Using Chiral Auxiliary Route
作者:Anil Karnik、Suchitra Kamath
DOI:10.1055/s-2008-1067098
日期:——
An enantioselective synthesis of 3-arylphthalides was achieved using ( S)-1-phenylethylamine as a chiral auxiliary. Reduction of chiral keto amides of 2-aroylbenzoicacids followed by acid-catalyzed lactonization yielded ( S)-3-arylphthalides with 75-85% ee.
Transition metal-catalyzed addition reactions of arylboronic acids with alkyl 2-formylbenzoates: efficient access to chiral 3-substituted phthalides
作者:Chun-Hui Xing、Yuan-Xi Liao、Ping He、Qiao-Sheng Hu
DOI:10.1039/c001104e
日期:——
Transition metal-catalyzed addition of arylboronicacids to 2-formylbenzoates afforded 3-substituted phthalides. By using SPINOL-based phosphites as ligands, a Rh(I)-catalyzed asymmetric version of such an addition reaction was achieved.