A Domino Process toward Functionally Dense Quaternary Carbons through Pd-Catalyzed Decarboxylative C(sp3)–C(sp3) Bond Formation
摘要:
An efficient protocol was developed to construct functionally dense quaternary carbons with concomitant formation of a new Csp(3)-Csp(3) bond via Pd-catalyzed decarboxylative transformation of vinyl cyclic carbonates. This redox-neutral catalytic system features stereocontrolled formation of multisubstituted allylic scaffolds with an aldehyde functionality generated in situ, and it typically can be performed at room temperature without any additives. DFT calculations provide a rationale toward the selective formation of these compounds and reveal a complex mechanism that with the help of microkinetic models is able to reproduce the nontrivial dependence of the identity of the product on the nature of the substituents in the substrate.
Palladium-Catalyzed [5 + 2] Annulation of Vinylethylene Carbonates with Barbiturate-Derived Alkenes
摘要:
A palladium/XantPhos-catalyzed [5 + 2] annulation of VECs with electron-deficient alkenes having an isolated carbon-carbon double bond has been developed to afford spirobarbiturate-tetrahydrooxepines. This study provides an expedient assembly of biologically interesting spirobarbiturate-tetrahydrooxepines. The easy scalability and versatile transformability of the reaction products were also exhibited.
carbonates (VECs) with diols has been developed. By using cooperative catalysts of the chiral palladium complex and triethylborane in mild conditions, the process gave monoetherified and bisetherified polyglycol derivatives with tetrasubstituted stereocenters in high yields with complete regioselectivities and high levels of enantio- and diastereoselectivities.
Palladium-Catalyzed Diastereoselective Formal [5 + 3] Cycloaddition for the Construction of Spirooxindoles Fused with an Eight-Membered Ring
作者:Ben Niu、Xiao-Yun Wu、Yin Wei、Min Shi
DOI:10.1021/acs.orglett.9b01748
日期:2019.6.21
A Pd-catalyzed formal [5 + 3] intermolecular cycloaddition reaction of isatin-derived α-(trifluoromethyl)imines with aryl substituted vinylethylene carbonates (VECs) has been reported, affording trifluoromethyl-group-containing spirooxindoles fused with an eight-membered ring as a single diastereoisomer in good yields in the presence of a Brønsted acid in a one-pot manner under mild conditions. The
Expedient Dual Co/Organophotoredox Catalyzed Stereoselective Synthesis of All‐Carbon Quaternary Centers
作者:Àlex Cristòfol、Bart Limburg、Arjan W. Kleij
DOI:10.1002/anie.202103479
日期:2021.7.5
An efficient and attractive Co/organophotoredox dualcatalysis protocol has been developed allowing the stereoselective access to a wide variety of syn-configured 1,3-diols featuring quaternary carbon centers. The synthesis of the target molecules is achieved under ambient reaction conditions using modular and accessible reagents, substituted vinyl cyclic carbonates and aldehydes, and in short reaction
Chiral Bidentate Phosphoramidite-Pd Catalyzed Asymmetric Decarboxylative Dipolar Cycloaddition for Multistereogenic Tetrahydrofurans with Cyclic <i>N</i>-Sulfonyl Ketimine Moieties
作者:Hao-Peng Lv、Xiao-Peng Yang、Bai-Lin Wang、Hao-Di Yang、Xing-Wang Wang、Zheng Wang
DOI:10.1021/acs.orglett.1c01411
日期:2021.6.18
An asymmetric [3 + 2] cycloaddition of vinyl ethylenecarbonates (VECs) and (E)-3-arylvinyl substituted benzo[d] isothiazole 1,1-dioxides has been developed using the Pd complex of a bidentate phosphoramidite (Me-BIPAM) as the catalyst, providing a wide variety of chiral multistereogenic vinyltetrahydrofurans in good yields with excellent diastereo- and enantioselectivities (up to >20:1 dr, 99% ee)
tertiary C-O bond via asymmetric allylicsubstitution of racemic vinylethylene carbonates with water and alcohols has been developed. Under the cooperative catalysis system of an in situ generated chiral palladium complex and boron reagent in mild conditions, the process allowed rapid access to valuable tertiary alcohols and ethers in high yields with complete regioselectivities and high enantioselectivities
已经开发了一种通过外消旋乙烯基碳酸亚乙酯与水和醇的不对称烯丙基取代对映选择性构建叔 CO 键的有效方法。在温和条件下原位生成的手性钯配合物和硼试剂的协同催化系统下,该过程允许以高产率快速获得有价值的叔醇和醚,具有完整的区域选择性和高对映选择性。该协议代表了与作为氧供体的水直接对映选择性形成三级 CO 键的第一个例子。该过程的合成效用已通过将产品加工成生物相关制剂的关键中间体来证明,