A copper-catalyzed 1,4-addition reaction of arylsulfonyl iodides with 1,3-enynes afforded various allenyl halides in high yields under mild conditions via a radical mechanism.

The CuBr2-catalyzed enantioselective allenylation of terminal alkynols with carbon chains of different lengths has been developed. Compared with (S)-α,α-diphenylprolinol, the reaction using (S)-α,α-dimethylprolinol as the chiral amine afforded optically active 1,3-disubstuted allenols with higher ee-values. Both aliphatic and aromatic aldehydes could be applied. The naturally occurring phlomic acid was synthesized in four steps from commercially available hex-5-yn-1-ol.

An unprecedented electrochemical heterodifunctionalization of α-CF3 alkenes with benzenesulfonyl hydrazides was accomplished in this work, wherein a β-sulfonyl and a α-hydroxyl group were simultaneously incorporated across the olefinic double bond...

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Community-based question answering (cQA) sites have accumulated vast amount of questions and corresponding crowdsourced answers over time. How to efficiently share the underlying information and knowledge from reliable (usually highly-reputable) answerers has become an increasingly popular research topic. A major challenge in cQA tasks is the accurate matching of high-quality answers w.r.t given questions. Many of traditional approaches likely recommend corresponding answers merely depending on the content similarity between questions and answers, therefore suffer from the sparsity bottleneck of cQA data. In this paper, we propose a novel framework which encodes not only the contents of question-answer(Q-A) but also the social interaction cues in the community to boost the cQA tasks. More specifically, our framework collaboratively utilizes the rich interaction among questions, answers and answerers to learn the relative quality rank of different answers w.r.t a same question. Moreover, the information in heterogeneous social networks is comprehensively employed to enhance the quality of question-answering (QA) matching by our deep random walk learning framework. Extensive experiments on a large-scale dataset from a real world cQA site show that leveraging the heterogeneous social information indeed achieves better performance than other state-of-the-art cQA methods.

Chiral molecules, which may contain one or more different type(s) of stereocentres, such as central, axial, planar, and helical chiralities, etc., are indispensable in chemistry, pharmaceutical industry, and life science. Despite many advances for the preparation of chiral molecules usually with a single type of chirality have been realized, simultaneous construction of different types of chiralities is still a significant challenge. Here, we wish to report a protocol for preparation of chiral allenes with both central and axial chiralities via a catalytic asymmetric allenylation of different biologically or synthetically useful fluorinated or non-fluorinated nucleophiles with readily available racemic allenes by using a single chiral ligand. An echoing between the central chirality and axial chirality for the enantioselectivity was observed. This strategy provides a general and practical approach to functionalized optically active allenes bearing both central and axial chiralities with an excellent enantioselectivity under mild conditions.

A Pd-catalyzed highly selective tandem reaction of allenynes, aryl or alkenyl iodides, and sodium azide for the synthesis of bicyclic 1,2,3-triazole derivatives with a very broad substrate scope including monosubstituted, 1,3-disubstituted, and trisubstituted allenynes as well as different types of organic iodides has been reported. Control experiments showed that the reaction went through a cascade allene difunctionalization/ Winstein allylic azide rearrangement/intramolecular azide-alkyne cycloaddition process. Scheme 2. The reactions of 1 j, 1 k, 1 l, and 1 m. Figure 2. ORTEP representations of cis-5 jf, E-5 kf, cis-5 lf, and 5 mf. Scheme 3. Control experiments. Scheme 4. The possible mechanism. E-5 kf: More polar. solid; m.p. 206.0-206.5°C (n-hexane/ DCM); 1 H NMR (300 MHz, CDCl 3 ) δ 7.78-7.58 (m, 4H, ArH), 7.57-7.42 (m, 4H, ArH), 7.42-7.30 (m, 3H, ArH), 7.08 (d, J = 8.4 Hz, 2H, ArH), 5.36 (t, J = 3.6 Hz, 1H, CH), 5.25 (t, J = 7.4 Hz, 1H, CH), 4.69 (d, J = 15.0 Hz, one proton of NCH 2 ), 4.30 (d, J = 15.0 Hz, one proton of CH 2 ), 3.62 (dd, J 1 = 12.6 Hz, J 2 = 4.8 Hz, one proton of CH 2 ), 3.31 (dd, J 1 = 12.8 Hz, J 2 = 4.2 Hz, one proton of CH 2 ), 2.43 (s, 3H, CH 3 ), 1.98-1.77 (m,

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