Transformations of N-arylpropiolamides to indoline-2,3-diones and acids via C≡C triple bond oxidative cleavage and C(sp^2)–H functionalization

A new palladium-catalyzed oxidative conversion of N-arylpropiolamides and H2O to various indoline-2,3-diones and acids through the C≡C triple bond cleavage and C(sp2)–H functionalization is described,which is promoted by a cooperative action of catalytic CuBr2,2,2,6,6-tetramethyl-1-piperidinyloxy(TEMPO)and O2.The method provides a practical tool for transformations of alkynes by means of a C–H functionalization strategy,which enables the formation of one C–C bond and multiple C–O bonds in a single reaction with high substrates compatibility and excellent functional group tolerance.     

Recent advances in radical-mediated [2+2+m] annulation of 1,n-enynes

1,n-Enynes are a versatile class of unsaturated hydrocarbons that found broad applications in the synthetic community of natural products, biologically active structures and functional materials. Typical methods for the transformations of 1,n-enynes include the radical-mediated [2+2+m] annulation reaction as they are particularly efficient accesses to functionalized polycyclic compounds. We herein highlighted recent process in the radical-mediated [2+2+m] annulation of 1,n-enynes, including [2+2+1] and[2+2+2] modes, for the construction of five-to six-membered-ring-fused polycyclic scaffolds. Meanwhile, the mechanisms for these transformations were described.     

金属催化二氯化物RCCl_2CH_2CH_2R~1合成反应的研究

在醇溶剂中，用金属或金属合金作为反应的催化剂，多氯化物RCCl_3和含吸电 子基的末端烯烃CH_2=CHR~1反应一步生成RCCl_2CH_2CH_2R~1。在此反应中，加成 反应和脱氯反应一步完成。     

Electrophilic ipso-cyclization of N-(p-methoxyaryl)propiolamides involving an electrophile-exchange process

A novel electrophilic ipso-cyclization involving an electrophile-exchange process has been developed. In the presence of CuX (X = I, Br, SCN) and electrophilic fluoride reagents, a variety of N-(p-methoxyaryl)propiolamides and 4-methoxyphenyl 3-phenylpropiolate were cyclized to selectively afford the corresponding spiro[4.5]decenones in moderate to good yields. It is noteworthy that two azaquaternary tricyclic products were synthesized through a two-step pathway involving an electrophilic ipso-cyclization and then an intramolecular Heck reaction.     

二氧化碳促进的醛和酮等羰基化合物烯丙基化反应研究

加入二氧化碳可以促进羰基化合物的烯丙基化反应. 实验结果表明: 在1.0 MPa的二氧化碳和2 equiv.的锡存在下, 以THF/H₂O为反应介质, 芳香醛化合物与烯丙基溴可以顺利地发生烯丙基化反应得到较高的产率, 而芳香酮化合物和脂肪醛等与烯丙基溴反应只得到较低的产率.     

Palladium-catalyzed C-H functionalization of N-arylpropiolamides with aryliodonium salts: selective synthesis of 3-(1-arylmethylene)oxindoles

A selective and efficient method for the synthesis of 3-(1-arylmethylene)oxindoles by palladium-catalyzed C-H functionalization of anilides with aryliodonium salts has been developed. In the presence of Pd(OAc)2 and Et3N, a variety of anilides underwent the reaction with aryliodonium salts to afford the corresponding 3-(1-arylmethylene)oxindoles in moderate to good yields. It is noteworthy that the reaction can be conducted providing moderate yields even without bases. The mechanism of the reaction was also discussed.     

Polymer-supported DABCO–palladium complex as a stable and reusable catalyst for room temperature Suzuki–Miyaura cross-couplings of aryl bromides

Polymer-supported DABCO–palladium complex was observed as to be efficient and reusable catalytic system for the Suzuki–Miyaura cross-coupling reaction. In the presence of 0.25 mol % of the polymer-supported DABCO–palladium complex, a variety of aryl bromides were coupled with arylboronic acids efficiently in an aqueous ethanol at room temperature under air. Moreover, the reaction was very rapid, and the catalyst could be recovered readily from the reaction by simple filtration and could be reused at least five times.     

Fe(0)催化三氯乙酸烯丙酯的环化反应研究

通过对Fe(O)催化烯烃自由基环化反应的研究，发现以Fe(O)为催化剂催化三氯 乙酸烯丙酯分子内自由基环化反应可以高化学选择性得到五元环内酯产物，反应中 不需加入配体。和大多数自由基反应一样，反应温度与催化剂用量对该反应的转化 率和产率有着很大的影响。     

Efficient palladium-catalyzed homocoupling reaction and Sonogashira cross-coupling reaction of terminal alkynes under aerobic conditions

An efficient method for palladium-catalyzed homocoupling reaction of terminal alkynes in the synthesis of symmetric diynes is presented. The results showed that both Pd(OAc)(2) and CuI played crucial roles in the reaction. In the presence of 2 mol % Pd(OAc)(2), 2 mol % CuI, 3 equiv of Dabco, and air, homocoupling of various terminal alkynes afforded the corresponding symmetrical diynes in moderate to excellent yields, whereas low yields were obtained without either Pd(OAc)(2) or CuI. Moreover, high TONs (turnover numbers; up to 940 000 for the reaction of phenylacetylene) for the homocoupling reaction were observed. Under similar reaction conditions, cross-coupling of 1-iodo-4-nitrobenzene with phenylacetylene was also carried out smoothly in quantitative yield. However, the presence of CuI disfavored the palladium-catalyzed Sonogashira cross-coupling reactions of the less active aryl iodides and bromides. In the presence of 0.01-2 mol % Pd(OAc)(2), a number of aryl iodides and bromides were coupled with terminal alkynes in good to excellent yields. It is noteworthy that this protocol employs mild, efficient, aerobic, copper-free, and ligand-free conditions.