Stereoconvergent Conjugate Addition of Arylboronic Acids to α-Angelica Lactone Derivatives: Synthesis of Stereochemically Complex γ-Butyrolactones
作者:Jessica A. Griswold、Jeffrey S. Johnson
DOI:10.1021/acscatal.9b04405
日期:2019.12.6
with up to threecontiguousstereocenters. The reaction proceeds under a dynamic kineticresolution manifold by isomerizing the achiral starting material into an interconverting mixture of enantiomeric conjugate acceptors, followed by catalyst-controlled, enantiomer-selective 1,4-addition. Base-promoted racemization of the intermediate α,β-butenolide is possible due to the high kinetic and thermodynamic
A directvinylogousMichael reaction of gamma-substituted deconjugated butenolides with nitroolefins has been developed with the help of a newly identified quinine-derived bifunctional catalyst, allowing the synthesis of densely functionalized products with contiguous quaternary and tertiary stereocenters in excellent yield with perfect diastereoselectivity (>20:1 dr) and high enantioselectivity (up
Catalytic asymmetric formal γ-allylation of deconjugated butenolides
作者:Amit K. Simlandy、Santanu Mukherjee
DOI:10.1039/c5ob02362a
日期:——
A formal γ-allylation of deconjugatedbutenolides is reported based on a two-step sequence consisting of a catalytic diastereo- and enantioselective vinylogous nucleophilic addition to vinyl sulfones and Julia–Kocienski olefination. This highly modular approach delivers densely functionalized butenolides containing a quaternarystereogenic centre in excellent yield with high enantioselectivity.
Diastereo- and Enantioselective Copper-Catalyzed Decarboxylative Ring-Opening [3 + 2] Annulation of Tertiary Propargylic Carbamates through Regioselective α-Attack of γ-Butenolides
作者:You-Wei Xu、Xiang-Ping Hu
DOI:10.1021/acs.orglett.9b03081
日期:2019.10.4
decarboxylative ring-opening [3 + 2] annulation of tertiary propargylic carbamates with γ-butenolides for the synthesis of optically active pyrrolidinones has been realized. The reaction proceeded through regioselective α-attack of γ-butenolide and generated highly congested vicinal tertiary and all-carbon quaternary stereocenters in pyrrolidinone scaffolds, featuring high stereoselective induction and broad functional
Access to chiral γ-butenolides <i>via</i> palladium-catalyzed asymmetric allylic C–H alkylation of 1,4-dienes
作者:Zhen-Yao Dai、Pu-Sheng Wang、Liu-Zhu Gong
DOI:10.1039/d1cc02295d
日期:——
Asymmetric allylic C–H alkylation of 1,4-pentadienes with α-angelica lactones has been developed by tri-axial phosphoramidite-palladium catalysis. This reaction can tolerate a range of functional groups under mild conditions, furnishing versatile chiral γ,γ-disubstituted butenolides in high yields with good to high levels of stereoselectivity.
已通过三轴亚磷酰胺-钯催化开发了 1,4-戊二烯与 α-当归内酯的不对称烯丙基 C - H 烷基化反应。该反应可以在温和条件下耐受一系列官能团,以高产率提供多功能手性 γ,γ-二取代丁烯内酯,具有良好到高水平的立体选择性。