Synthesis of novel chiral phosphine-triazine ligand derived fromα-phenylethylamine for Pd-catalyzed asymmetric allylic alkylation

A novel chiral phosphine-triazine ligand was synthesized from chiral α-phenylethylamine through a three-step procedure. In a model reaction of Pd-catalyzed allylic alkylation of rac-1,3-diphenylprop-2-en-1-y1 pivalate with dimethyl malonate, good enantioselectivity （90% e.e.） was obtained by using this ligand.

Synthesis of (+) or (-)-2-(8′-Diphenylphosphino-1′-naphthyl)oxazoline Ligands and Their Application in Pd-Catalyzed Allylic Alkylation Reaction

We synthesized optically active 2-(8′-diphenylphosphino-1′-naphthyl)oxazoline ligands by palladium-catalyzed coupling reactions of (trimethylsilyl)diphenylphosphine with 2-(8′-bromo-1′-naphthyl)oxazolines, which, in turn, were prepared from 8-bromo-1-naphthoyl chloride by the reaction with natural optical active amino alcohols. Pd-Catalyzed allylic alkylation reaction induced by these chiral ligands gave the allylic substituted products in high yields and moderate ee values.

Regioselective and asymmetric allylic alkylation of vinyl epoxides for the construction of allylic alcohols via synergistic catalysis

A highly efficient asymmetric allylic alkylation of cyclic and acyclic carbon nucleophiles with vinyl epoxides has been developed,which exhibits good functional group compatibility,high atomic and step economy.This protocol utilizes a strategy of synergistic catalysis with a chiral N,N'-dioxide/Ni~Ⅱ complex and an achiral Pd~0 catalyst,generating a series of multisubstituted allylic alcohols with a quaternary carbon stereocenter in high yield and excellent regio-,Z/E-and enantioselectivity under mild conditions.Further transformations of the product demonstrate the potential utility of this protocol in the synthesis of allyl alcohol derivatives and natural product analogues.Experimental studies revealed that the N,N′-dioxide/metal complexes play an important role in controlling the Z/E-and enantioselectivity.The density functional theory(DFT) calculations further demonstrated that multiple C–H···π interactions between the aromatic rings of the two substrates and the amide moiety in the ligand stabilized the dominant transition state.

Palladium-catalyzed allylic alkylation enabled by ketone umpolung via Pudovik addition/[1,2]-phospha-Brook rearrangement

Palladium-catalyzed allylic alkylation enabled by ketone umpolung via Pudovik addition/[1,2]-phospha-Brook rearrangement with phosphites has been developed.The protocol offers a straightforward method for the synthesis of potentially bioactive homoallylic alcohol phosphonates in an efficient and economical way.This cascade reaction proceeds under mild conditions with excellent functional group compatibility.Furthermore,the catalytic asymmetric version has also been explored.

Palladium-catalyzed annulative allylic alkylation for regioselective construction of indole-fused medium-sized cyclic etherS

A new palladium-catalyzed annulative allylic alkylation(AAA)reaction of 2-(indol-2-yl)phenols with dual allylic electrophiles such as isobutylene dicarbonate and butene dicarbonate is described,leading to the regioselective synthesis of tetracyclic medium-sized cyclic ethers possessing a bridged aryl-indole scaf-fold,namely,benzo[2,3]oxocino[4,5-b]indoles and benzo[2,3]oxepino[4,5-b]indoles,in good to excellent yields.This protocol demonstrates a broad substrate scope,good compatibility with substituents and high regioselectivity,providing a catalytic and flexible method for creating bridged aryl-indole skeletons.

Enantioselective O-allylic alkylation of Morita-Baylis-Hillman carbonates with oxime

The enantioselective O-allylic alkylation of acetophenone oxime with various Morita-Baylis-Hillman (MBH) carbonates has been accomplished by the catalysis of a commercially available cinchona alkaloid (DHQD)2PHAL. The corresponding O-allylic products were obtained in moderate to excellent yields up to 96% ee.

Palladium-catalyzed asymmetric allylic C–H alkylation of 1,4-dienes and glycine Schiff bases

A highly regio-and enantioselective allylic C–H alkylation of 1,4-dienes with glycine Schiff bases has been established by chiral palladium-phosphoramidite catalysis. This reaction can proceed under mild conditions and tolerate a wide scope of 1,4-dienes,delivering structurally diverse chiral β-branched α-amino acid surrogates in moderate to high yields and with high levels of regio-, Z/E-, diastereo-and enantioselectivities.

Palladium-Catalyzed Asymmetric Allylic Alkylation/α-Iminol Rearrangement:A Facile Access to 2-Spirocyclic-Indoline Derivatives

We report an unprecedented Pd-catalyzed asymmetric allylic alkylation of 1-(indol-2-yl)cyclobutanols followed by anα-iminol rearrangement.High yields with excellent chemo-,regio-,diastereo-,and enantioselectivities have been realized,affording a wide range of enantioenriched 2-spirocyclicindolines bearing two contiguous stereocenters.The facial selectivity of the ensuing rearrangement is controlled by the subtle difference of the substituents on the all-carbon quaternary stereogenic center formed in the allylic alkylation step.Nonactivated racemic terminal allylic alcohols are utilized as efficient electrophiles via kinetic resolution pathways for the first time in Pd-catalyzed asymmetric allylic alkylation.The role of Et3B additive is pivotal to activating allylic alcohols toward the formation of π-allylpalladium species and suppressing N/O allylic alkylation of indole with enhanced C3-nucleophilicity.Electrospray ionization high-resolution mass spectrometry(ESIHRMS)experiments provided strong evidence for the existence of the key nucleophilic boron anionic species,which fully accounts for the essential role of the Et_(3)B additive.The study of the mechanism indicates that the real catalytically active species is an electronic π-cinnamyl-palladium complex coordinated by two phosphoramidite ligands,which is consistent with the observed nonlinear effect and control experiments and is further confirmed by X-ray structure analysis.

Platinum-Catalyzed Allylic C-H Alkylation with Malononitriles

The direct functionalization of allylic C-H bonds is distinguished by enabling rapid assembly of structural complexity from simple molecules.Although Pd-catalyzed allylic C-H functionalization has been extensively studied,the discovery of new catalytic systems remains fairly underdeveloped.Here,we disclose a Pt-catalyzed allylic C-H alkylation of a wide range of α-alkenes by using phosphoramidites as ligands and malononitriles as alkylating reagents.Notably,the combination of chiral ureacatalyzed Michael addition and Pt-catalyzed allylic C-H alkylation can serve as an efficient protocol to access chiral tetrahydropyran with high levels of diastereo-and enantioselectivity.Mechanistic studies suggest that the Pt-catalyzed allylic C-H activation proceeds through a concerted proton and two-electron transfer process,which is analogous to transition state geometries of Pd catalysis.

Organocatalytic asymmetric allylic alkylation of sulfonylimidates with Morita-Baylis-Hillman carbonates

The asymmetric allylic alkylation reaction of sulfonylimidates with various Morita-Baylis-Hillman (MBH) carbonates was accomplished by the catalysis of commercially available cinchona alkaloids catalyst (DHQD)2AQN.The corresponding allylic alkylation products were obtained in good yields with high stereoselectivities (up to 99% ee,89:11 dr).

Regioselective Synthesis of Functionalized Dihydroquinolines via Organocatalytic Allylic Alkylation

The regioselective allylic alkylation of 1,2-dihydroquinolines and Morita-Baylis-Hillman（MBH） adducts has been developed. By surveying various reaction parameters, we summarized the effects of temperatures, relative reactant doses, catalysts, solvents and N-protected groups on the regioselectivity of this transformation. This method provides a facile protocol for the preparation of allylic a-substituted dihydroquinolines.

Polymer-Supported Chiral Monodentate Phosphoramidites in Palladium-Catalyzed Allylic Alkylation Reactions

A new and simple method for immobilization of monodentate chiral ligand on the cheap resin has been developed. A series of resin-immobilized phosphoramidite ligands based on BINOL and TADDOL backbones have been synthesized and characterized with gel-phase NMR. The immobilized ligands have been applied to the Pd-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate. Among four ligands, the supported bulky monodentate phosphoramidite ligand based on TADDOL backbone afforded the chiral product with ee up to 65%; moreover, this ligand could be recycled for 3 times without substantial decrease of the conversion and ee.

New Chiral N,S-Ligands with Thiophenyl at Benzylic Position. Palladium(II)-catalyzed Enantioselective Allylic Alkylation

bState Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China cShanghai Hong Kong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China New chiral N,S ligands with oxazoline and thiophenyl substituents at benzene ring and benzylic position have been prepared and applied in palladium catalyzed asymmetric allylic alkylation reaction to provide the product with high yield and entantioselectivity ( 82%-93% ee ).

Visible-light-promoted radical alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester: Synthesis of oxazolines

An efficient photocatalytic alkylation/cyclization of allylic amide with N-hydroxyphthalimide ester has been developed. The transformation is taken advantage of alkyl radicals to attack allylic amide with the assist of inexpensive rose bengal as photocatalyst to prepare a series of alkyl substituted oxazolines in moderate to excellent yields. High regioselectivity, operational safety, mild conditions and excellent substrate generality give this protocol broad application prospects.

新型手性硫醚-亚磷酰胺配体的设计与应用

根据模块组合法,设计并合成了一种具有亚磷酰胺结构的硫醚配体,该配体具有原料便宜易得、合成步骤简单、易于修饰和结构稳定等特点。以配体/钯络合物催化的丙二酸二甲酯与1,3-二苯基烯丙基醋酸酯的烯丙基化反应作为模板反应,探究了溶剂和碱对其立体控制的影响。随后探究了中心手性与轴手性的匹配/错配现象以及硫醚片段的空间位阻和电性对反应立体控制的作用。在最佳条件下,产物的对映选择性能够达到-76%ee。

Three-Component Barbier Allylation-Friedel-Crafts Alkylation Promoted by BuPyCI/SnCI2·2H2O： Application to the Synthesis of 4-（Substituted phenyl）chromans

Barbier allylation and Friedel-Crafts alkylation of （un）substituted benzaldehydes, allylbromide and phenols can be combined in a one-pot process in ionic liquid （BuPyC1/SnC12·2H2O） to directly synthesize 4-（2-hydroxyphenyl）- 4-[（un）substituted phenyl]but-1-ene compounds, which were applied to the synthesis of 4-（substituted phenyl）- chromans through intramolecular cyclization reactions.

Allylation and alkylation of oxindoleketimines via imine umpolung strategy

When treated with an alkoxide base like t-BuOK in aprotic solvent,N-di phenyl methyl imino oxindoles,made conveniently through condensation of corresponding isatins with N-di phenyl methyl amine,are deprotonated to form azaallyl anions.Allylation and alkylation of this type of intermediates proceed smoothly with diverse C-electrophiles.Acidic work up finishes 3-amino-3-allyl/alkyl oxindoles.The overall transformation equals to an umpolung process at the C3 of isatins.

醚化封端聚醚的技术进展

对醚化封端聚醚的合成方法、分子结构对产品性能的影响进行讨论 。

二乙基烯丙基胺的合成

以烯丙基氯作烷基化试剂 ,在常压、不加催化剂的情况下合成了二乙基烯丙基胺 ,并对原料配比、水浴温度、加料方式与时间、以及沸腾反应时间对产率的影响进行了研究 .结果表明 ,在烯丙基氯与二乙胺摩尔比为 1.1∶1、总加料时间 2h及沸腾反应 1h时 ,二乙基烯丙基胺的产率可达 78% .

1,3-溴氯丙烷的选择性反应

目的 通过合成 1-甲氧基 - 3-氯丙烷 ,确立烯丙氯的新合成方法。方法和结果 烯丙氯可由 1,3-溴氯丙烷和甲醇钠在甲醇中加热合成得到 ;在苯中回流则得到 1-甲氧基 - 3-氯丙烷。