Highly Stereoselective Chemoenzymatic Synthesis of the 3H-Isobenzofuran Skeleton. Access to Enantiopure 3-Methylphthalides
摘要:
A straightforward synthesis of (S)-3-methylphthalides has been developed, with the key asymmetric step being the bioreduction of 2-acetylbenzonitriles. Enzymatic processes have been found to be highly dependent on the pH value, with acidic conditions being required to avoid undesired side reactions. Baker's yeast was found lobe the best biocatalyst acting in a highly stereoselective fashion. The simple treatment of the reaction crudes with aqueous HCl has provided access to enantiopure (S)-3-methylphthalides in moderate to excellent yields.
Palladium-Catalyzed Sequential Acylation/Cyanation of Aryl Iodides: A Regiospecific Synthesis of 2-Cyanoaryl Ketones
作者:Shanfei Pan、Feifei Wu、Ruicheng Yu、Wanzhi Chen
DOI:10.1021/acs.joc.5b02710
日期:2016.2.19
A palladium-catalyzed, norbornene-mediated acylation/cyanation reaction of iodobenzene was developed by the use of acyl chlorides as acylation reagents and cuprous cyanide. The reaction gave the 2-cyanoaryl ketones efficiently by using readily available starting materials.
d Catellani-type ortho-C–H-acylation/ipso-cyanation of iodoarenes is developed via a three-component approach using safe and low-toxic sodium carboxylates as the acyl sources and CuCN as the CN source, affording the desired products in yields of 50–94%. Without introducing a directing group on the substrate, a catalytic amount of norbornene and palladium can regioselectively activate the ortho-C–H