Stereoselective synthesis of 4-alkylidene pyrrolidinones and pyrrolizidinones
摘要:
alpha-Aminoalkylcuprates prepared from tert-butoxycarbonyl protected amines undergo a conjugate addition reaction with alpha,beta-beta,gamma-allenyl esters to afford the corresponding beta,gamma-unsaturated esters with a high degree of stereoselectivity. Treatment of the unsaturated esters with PhOH/TMSCl or catechol boron bromide effects amine deprotection and lactamization to afford a 4-alkylidene-2-pyrrolidinone ring with preservation of the original olefin stereochemistry. The method can be used to prepare 4-alkylidene 2-pyrrolidinones and 2-pyrrolizidinones (C) 1999 Elsevier Science Ltd. All rights reserved.
Manganese-Catalyzed C−H Annulation of Ketimines with Allenes: Stereoselective Synthesis of 1-Aminoindanes
作者:Chong Lei、Lijie Peng、Ke Ding
DOI:10.1002/adsc.201800465
日期:2018.8.6
A manganese‐catalyzed C−H annulation of ketimines with poly‐substituted ester‐activated allenes toward the synthesis of 1‐aminoindanes bearing two vicinal all‐substituted carbon stereocenters and an exocyclic double bond was developed. The reaction features high diastereoselectivity, high E/Z selectivity, 100% atom‐economy, broad substrate scope and good functional group tolerance.
Design, synthesis and application of a new type of bifunctional Le-Phos in highly enantioselective γ-addition reactions of N-centered nucleophiles to allenoates
作者:Haile Qiu、Xiaofeng Chen、Junliang Zhang
DOI:10.1039/c9sc04073k
日期:——
A novel class of bifunctional cyclic phosphine catalysts (Le-Phos) is reported, which showed good performances in enantioselective γ-addition reactions of N-centered nucleophiles and allenoates under mild conditions.
Synthesis of highly substituted oxetanes via [2+2] cycloaddition reactions of allenoates catalyzed by a guanidine Lewis base
作者:Philipp Selig、Aleksej Turočkin、William Raven
DOI:10.1039/c3cc40855h
日期:——
The first synthesis of highly substituted 3-alkyl-oxetan-2-ylidenes from allenoates was developed by using the bicyclic guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as an exceptionally active nitrogen Lewis base catalyst.
Palladium-Catalyzed Cocyclotrimerization of Allenes with Arynes: Selective Synthesis of Phenanthrenes
作者:Yi-Lin Liu、Yun Liang、Shao-Feng Pi、Xiao-Cheng Huang、Jin-Heng Li
DOI:10.1021/jo900117c
日期:2009.4.17
Palladium-catalyzed cocyclotrimerization of allenes with arynes has been developed for selectively synthesizing phenanthrenes. In the presence of [(allyl)PdCl]2 and P(o-tol)3, a variety of allenes, including internal and terminal allenes, underwent the cocyclotrimerization with arynes to afford the corresponding phenanthrenes in moderate to good yields. The results showed the selectivity of the reaction
contiguous three stereocenters has been a long-standing challenging task in organic synthesis. Herein we present a phoshine-catalyzed highly regio-, diastereo- and enantioselective [3+2] cycloaddition of γ-substitutedallenoates with β-perfluoroalkyl enones, delivering a wide range of densely functionalized perfluoroalkylated cyclopentenes with three contiguous chiral stereocenters.