Catalytic, Enantioselective α‐Alkylation of Azlactones with Nonconjugated Alkenes by Directed Nucleopalladation
作者:Sri Krishna Nimmagadda、Mingyu Liu、Malkanthi K. Karunananda、De‐Wei Gao、Omar Apolinar、Jason S. Chen、Peng Liu、Keary M. Engle
DOI:10.1002/anie.201814272
日期:2019.3.18
palladium(II)‐catalyzed enantioselective α‐alkylation of azlactones with nonconjugated alkenes is described. The reaction employs a chiral BINOL‐derived phosphoric acid as the source of stereoinduction, and a cleavable bidentate directing group appended to the alkene to control the regioselectivity and stabilize the nucleopalladated alkylpalladium(II) intermediate in the catalytic cycle. A wide range of
Asymmetric construction of dihydrobenzofuran-2,5-dione derivatives <i>via</i> desymmetrization of <i>p</i>-quinols with azlactones
作者:Lihua Xie、Shunxi Dong、Qian Zhang、Xiaoming Feng、Xiaohua Liu
DOI:10.1039/c8cc08985j
日期:——
3-Amino-benzofuran-2,5-diones containing a chiral amino acid residue were achieved through BG-1·HBPh4 catalyzed enantioselective Michael addition/lactonization cascade reaction of p-quinols with azlactones.
Organocatalyzed Asymmetric 1,4-Addition of Azlactones to α,β-Unsaturated Trichloromethyl Ketones: Synthesis of α,α-Disubstituted α-Amino Acid Derivatives
作者:Jinlong Zhang、Xihong Liu、Chongyang Wu、Panpan Zhang、Jianbo Chen、Rui Wang
DOI:10.1002/ejoc.201403158
日期:2014.11
4-addition of azlactones to α,β-unsaturated trichloromethyl ketonescatalyzed by cinchonaalkaloid derived bifunctional thiourea catalysts was developed. A series of α,α-disubstituted α-amino acid derivatives bearing a quaternary stereocenter at the α-position were obtained in high yields with excellent diastereo- and enantioselectivities (up to -20:1 dr and 99% ee). In addition, the trichloromethyl moiety
Brønsted Acid Accelerated Pd-Catalyzed Direct Asymmetric Allylic Alkylation of Azlactones with Simple Allylic Alcohols: A Practical Access to Quaternary Allylic Amino Acid Derivatives
A Brønsted acid accelerated Pd-catalyzed asymmetric allylicalkylation of azlactones with simple allylicalcohols under mild reaction conditions has been realized, which provides a direct and readily scalable approach for the synthesis of all-carbon quaternary allylic amino acid derivatives in excellent yields and good enantioselectivities.
Enantioselective synthesis of pyrano[2,3-<i>c</i>]pyrrole <i>via</i> an organocatalytic [4 + 2] cyclization reaction of dioxopyrrolidines and azlactones
cyclization reaction of dioxopyrrolidines and azlactones has been successfully developed through a squaramide catalysis strategy. This protocol provides an efficient and mild access to obtain pyrano[2,3-c]pyrrole scaffolds containing contiguous quaternary and tertiary stereogenic centers in excellent yields (up to 99%) with high levels of diastereo- and enantioselectivities (up to 99% ee). Two possible pathways
二氧吡咯烷和氮杂内酯的对映选择性[4 + 2]环化反应已通过方酰胺催化策略成功开发。该协议提供了高效,温和的途径来获得吡喃并[2,3- c ]吡咯支架,该支架包含连续的四级和三级立体异构中心,产率高(高达99%),非对映和对映选择性高(ee高达99%) )。提出了两种可能的途径来解释观察到的立体选择性。