meso-dicarbonatecyclohexene with β-hydrazino carboxylic esters has been achieved via a RuPHOX/Pd-catalyzed allylic substitution cascade for the construction of chiral hexahydrocinnoline derivatives with high performance. Mechanistic studies reveal that the reaction exploits a pathway different from that of our previous work and that the first nitrogen nucleophilic process is the rate-determining step. The protocol
Pd-Catalyzed Allylic Alkylation Cascade with Dihydropyrans: Regioselective Synthesis of Furo[3,2-<i>c</i>]pyrans
作者:Mark J. Bartlett、Claire A. Turner、Joanne E. Harvey
DOI:10.1021/ol400902d
日期:2013.5.17
A regioselective palladium-catalyzed allylic alkylation cascade forms furo[3,2-c]pyrans from various cyclic β-dicarbonyl bis-nucleophiles and 3,6-dihydro-2H-pyran bis-electrophiles. The combination of allylic carbonate and anomeric siloxy leaving groups in the dihydropyran substrate allows control of the many regiochemical possibilities in this reaction. Annulation proceeds stereoconvergently to give
区域选择性钯催化的烯丙基烷基化级联反应由各种环状β-二羰基双亲核试剂和3,6-二氢-2 H-吡喃双亲电试剂形成呋喃[3,2- c ]吡喃。二氢吡喃底物中的烯丙基碳酸酯和异头甲硅烷氧基离去基团的组合允许控制该反应中许多区域化学的可能性。环合进行立体会聚,以从顺式或反式取代的起始原料产生顺式融合的呋喃吡喃。
Pd‐Catalyzed Asymmetric Allylic Substitution Annulation Using Enolizable Ketimines as Nucleophiles: An Alternative Approach to Chiral Tetrahydroindoles
A synthesis of chiral tetrahydroindoles has been developed via a Pd‐catalyzed asymmetricallylicsubstitution annulation using unstable enolizable ketimines as nucleophiles and our previously developed tBu‐RuPHOX as a chiral ligand. The reaction proceeds via an asymmetric desymmetrization of the meso‐diacetatecycloalkenes, providing the desired chiral tetrahydroindoles in moderate to good yields and
Acetoxy Meldrum’s Acid: A Versatile Acyl Anion Equivalent in the Pd-Catalyzed Asymmetric Allylic Alkylation
作者:Barry M. Trost、Maksim Osipov、Philip S. J. Kaib、Mark T. Sorum
DOI:10.1021/ol2011242
日期:2011.6.17
Acetoxy Meldrum’s acid can serve as a versatile acylanionequivalent in the Pd-catalyzed asymmetric allylic alkylation. The reaction of this nucleophile with various meso and racemic electrophiles afforded alkylated products in high yields and enantiopurities. These enantioenriched products are versatile intermediates that can be further functionalized using nitrogen- and oxygen-centered nucleophiles
Acetoxy Meldrum 的酸可以在 Pd 催化的不对称烯丙基烷基化中用作通用的酰基阴离子等价物。该亲核试剂与各种内消旋和外消旋亲电试剂的反应以高产率和对映纯度提供烷基化产物。这些对映体富集的产品是多功能中间体,可以使用以氮和氧为中心的亲核试剂进一步功能化,为合成核苷类似物提供多功能支架。这些支架用于完成抗 HIV 药物卡波韦、阿巴卡韦和抗生素阿里斯特霉素的正式合成。
Desymmetrization of meso-2-Alkene-1,4-diol Derivatives through Copper(I)-Catalyzed Asymmetric Boryl Substitution and Stereoselective Allylation of Aldehydes
Breaking the mirror: The reaction sequence described in the title was applied to the synthesis of a valuable chiral drug precursor and the rapid stereoselective assembly of complex compounds with multiple chiral centers (see scheme).