M(OTf)_3催化N－烷氧羰基吡咯或噻吩醛和盐酸伯胺的新颖Mannich反应

三氟甲磺酸盐M(OTf)_3 (M = Sc, Y, Ln)在水相中能较好地催化N－烷氧羰基 吡咯或噻吩与甲醛和盐酸伯胺的新颖的Mannich反应,其中Y(OTf)_3催化效果最佳 。该反应具有条件温和,收率较高和原子经济性等优点,为N－烷氧羰基吡咯和噻 吩类Mannich碱的合成提供了一种新方法,同时该反应以水为主要溶剂溶剂,符合 当今绿色化学的发展趋势。     

Yb(OTf)3催化固体光气对有机酸酰氯化反应

与传统的酰氯化试剂相比,固体光气(BTC)是一种性能较好的酰氯化试剂,将其用于各种芳香酸和脂肪酸酰氯化反应,均取得较高的转化率(99%);此外,稀土Lewis酸对该固体光气和有机酸所进行的酰氯化反应具有一定催化作用。     

One-pot Three-component Mannich Reaction Catalyzed by 2-Hydroxylpyridine

An effcient synthetic protocol for the β-amino carbonyl compounds was developed via one-pot three-component Mannich reaction of aromatic aldehydes, aromatic amines and cyclohexanone catalyzed by 2-hydroxylpy-ridine under mild reaction conditions. β-Amino carbonyl compounds were obtained in moderate to good yields and reasonable diastereoselectivities. The effects of different solvents, catalyst amounts and the scope of different substrates on the Mannich reactions were investigated. The plausible reaction mechanism was also discussed.     

Yb(OTf)3催化苯乙酮、芳香醛和芳香胺的Mannich反应:三组分 "一锅法"合成β-氨基酮衍生物

报道了稀土化合物Yb(OTf)3催化的苯乙酮、芳香醛和芳香胺Mannich反应,三组分"一锅法"合成了一系列的β-氨基酮衍生物.该方法操作简单、条件温和、产率较高、催化剂可重复使用,且对环境友好.     

稀土化合物Yb(OTf)3催化的有机合成反应的最新进展

研究和开发环境友好的有机合成反应是"绿色化学"研究的一个重要内容,其中也包括新型绿色催化剂的研究.本文对近两年来Yb(OTf)3作为催化剂的有机合成反应按照反应类型进行了综述.进一步总结和拓展了Yb(OTf)3的催化范围,证明了稀土化合物广泛的应用前景.     

无溶剂条件下Yb(OTf)3催化的亚甲基化合物和醛的Knoevenagel反应

在Yb(OTf)₃催化下, 不用任何溶剂, 将活泼亚甲基化合物和各类醛进行Knoevenagel反应, 得到相应的取代烯烃衍生物. 此法操作简便, 对环境友好, 具有很高的反应产率, 且副产物少; 此外, 催化剂能够在进行反复回收利用之后仍然保持很高的催化活性.     

Yb(OTf)3催化苯乙酮、芳香醛和芳香胺的Mannich反应: 三组分“一锅法”合成β-氨基酮衍生物

报道了稀土化合物Yb(OTf)₃催化的苯乙酮、芳香醛和芳香胺Mannich反应, 三组分“一锅法”合成了一系列的β-氨基酮衍生物. 该方法操作简单、条件温和、产率较高、催化剂可重复使用, 且对环境友好.     

Yb(OTf)3催化下用研磨法合成喹喔啉-2,3-二酮衍生物

将邻苯二胺衍生物、草酸以及催化剂Yb(Otf)3置于研钵中, 不加任何溶剂, 在室温下进行固相研磨, 以较高的产率得到产物喹喔啉-2, 3-二酮衍生物. 该法反应条件温和, 操作简便, 且对环境友好.     

水介质中Yb(OTf)3催化下喹唑啉酮衍生物的绿色合成

在水介质中,醛或酮首先和邻氨基苯甲酰肼反应形成腙;在1 mol％ Yb(OTf)3催化下,再与另外一分子醛或酮反应,构建一系列不同取代的喹唑啉酮衍生物.该方法具有中性反应条件、产率高(80％～94％)、操作简单和环境友好等优点.产物的结构通过IR,1H NMR和HRMS表征.     

One-Pot Syntheses of 3,4-Dihydropyrimidine-2(1H)-thiones Catalyzed by La(OTf)_3

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Direct Catalytic Asymmetric Mannich Reaction with Dithiomalonates as Excellent Mannich Donors: Organocatalytic Synthesis of (R)‐Sitagliptin

In this study, dithiomalonates (DTMs) were demonstrated to be exceptionally efficient Mannich donors in terms of reactivity and stereoselectivity in cinchona‐based‐squaramide‐catalyzed enantioselective Mannich reactions of diverse imines or α‐amidosulfones as imine surrogates. Owing to the superior reactivity of DTMs as compared to conventional malonates, the catalyst loading could be reduced to 0.1 mol % without the erosion of enantioselectivity (up to 99 % ee). Furthermore, by the use of a DTM, even some highly challenging primary alkyl α‐amidosulfones were smoothly converted into the desired adducts with excellent enantioselectivity (up to 97 % ee), whereas the use of a malonate or monothiomalonate resulted in no reaction under identical conditions. The synthetic utility of the chiral Mannich adducts obtained from primary alkyl substrates was highlighted by the organocatalytic, coupling‐reagent‐free synthesis of the antidiabetic drug (?)‐(R)‐sitagliptin.     

Ga(ClO4)3-catalyzed Reaction of 1,2-Diamines and α-Bromoketones: Synthesis of 2-Substituted Quinoxalines

Ga(ClO₄)₃-catalyzed reaction of 1,2-aryldiamines and α-bromoketones to afford 2-substituted quinoxa- lines in good yields is described. The reaction proceeded via grinding process with 10%(molar fraction) catalyst under solvent-free conditions at room temperature. For unsymmetrical o-phenylenediamines bearing electron-with- drawing groups, regio-selective quinoxalines were obtained.     

In(OTf)_3 catalyzed allylation reaction of imines with tetraallyltin

In the presence of catalytic amount of In(OTf)3 (10 mol%), a series of aldimines reacted with tetraallyltin in a 2:1 molar ratio to afford the corresponding homoallylic amines in good yields. The good atom efficiency was achieved under mild reaction conditions and a new protocol (allyl)4Sn/In(OTf)3 for simple imines was developed.     

Solvent-switchable Acetalization by Yb（OTf）3-Catalyzed Procedures

O,O＇Diethyl acetals were prepared in high yields under mild conditions via the reaction of triethyl orthoformate with aldehydes and ketones in absolute ethanol in the presence of as low as 0.1 tool% of Yb（OTf）3. Using the same catalyst in THF-H2O, these O,O＇-diethyl acetals could be converted to the corresponding carbonyl compounds efficiently. This new protection-deprotection protocol presents the advantages of ease of execution, high efficiency and good chemoselectivity.     

Hf(OTf)4-Catalyzed Three-Component Synthesis of N-Carbamate-Protected β-Amino Ketones

Hafnium(IV) triflate (Hf(OTf)₄) has been identified as a potent catalyst for the direct three-component synthesis of β-carbamate ketones. This new method, featuring a low catalyst loading, fast reaction rate, and solvent-free conditions, provided facile access to a diversity of carbamate-protected Mannich bases. A mechanistic investigation indicated that the three-component reaction proceeds via sequential aldol condensation and aza-Michael addition, but not the Mannich-type pathway.     

离子液体中Yb(OTf)_3催化下喹唑啉酮衍生物的绿色合成

以邻氨基苯甲酰胺和芳醛为原料,离子液体[BMIm]Br为溶剂,Yb(OTf)3为催化剂室温下合成了一系列的2-芳基-2,3-二氢化喹唑啉-4-(1H)-酮衍生物.和其他方法相比,该方法具有反应条件温和、产率高(85%～96%)、环境友好等优点.产物的结构通过熔点,IR,1H NMR和高分辨质谱分析确证.     

In(OTf)3 catalysed simple one-pot synthesis of α-amino phosphonates

A new efficient one-pot synthesis of α-amino phosphonates derived from nitro substituted anilines, aldehydes and diethyl phosphite has been carried out by employing 5 mol% of In(OTf)₃. The method is equally effective for the generation of α-amino phosphonates from various carbonyl compounds and other amines.     

One—Pot Synthese of 3,4—Dihydropyrimidine—2（1H）—thiones Catalyzed by La（OTf）3

A general and practical procedure for the syntheses of 3,4-di-hydropyrimidine-2(1H)-thiones by a one-pot condensation of aldehyde,β-ketoester or β-diketone and thiourea using La(OTf)3 as the catalyst is described.Mild reaction conditions,excellent yields as well as the environmentally friendly character of La(OTf)3 make it an important alternative to the classic acid-catalyzed Biginelli‘s reaction.     

手性Salen及Ga(Salen)催化苯基锂对环氧环己烷对映选择性开环反应

合成了14个含1,2-环己二胺、1,2-二苯基乙二胺或邻苯二胺的手性Salen化合物, 研究了手性Salen直接催化苯基锂对环氧环己烷的不对称开环反应, 结果表明二胺的结构和苯环上3,3'-位取代基对反应的对映选择性有很大的影响. 用Salen与 Me₃Ga原位生成的Ga(Salen)催化苯基锂对环氧环己烷的不对称开环反应, 与用Salen直接催化相比, 得到了更好的化学产率和对映选择性. 当用Ga(Slane) 15为催化剂时, 最佳ee值为73%.