Diastereoselective three-component synthesis of beta-amino carbonyl compounds using diazo compounds, boranes, and acyl imines under catalyst-free conditions

Diazo compounds, boranes, and acyl imines undergo a three-component Mannich condensation reaction under catalyst-free conditions to give the anti β-amino carbonyl compounds in high diastereoselectivity. The reaction tolerates a variety of functional groups, and an asymmetric variant was achieved using the (−)-phenylmenthol as chiral auxiliary in good yield and selectivity. These β-amino carbonyl compounds are valuable intermediates, which can be transformed to many potential bioactive molecules.We gratefully acknowledge Philip N. Moquist for editorial review of the manuscript. Preliminary experiments were performed by Y.L. at Boston University. Completion of the work was accomplished under the direction of G.W. at the University of Science and Technology Beijing, China. S.E.S. and Y.L. gratefully acknowledge the NIH for support (NIGMS R01 GM078240). Y.L., J.Y., and G.W. thank the Innovative Foundation from China National Petroleum Corporation (Grant No. 2012D-5006-0504) for financial support. Y.L. also thanks the Beijing Natural Science Foundation (Grant No. 2144052) and China Postdoctoral Science Foundation (2013M540859) for financial support. (NIGMS R01 GM078240 - NIH; 2012D-5006-0504 - Innovative Foundation from China National Petroleum Corporation; 2144052 - Beijing Natural Science Foundation; 2013M540859 - China Postdoctoral Science Foundation)Published versio

An Analysis of Reader Engagement in Linguistic Research Articles

This study investigated the use of reader engagement in 60 RAs from the international linguistic journal Language Learning Based on the Model of Stance and Engagement and IMRD Structure under Genre Analysis theory findings suggested that there appear a total of 53 1 reader engagement markers per 10 000 words Under IMRD Structure reader engagement markers occur most frequently in Introduction section 76 9 words per 10 000 words followed by Discussion Method and Results There exists a significant difference of the distribution in reader engagement markers among the four sections X2 22 747 df 3 p 001 Under the Model of Stance and Engagement the frequency of Directives category 102 8 times per 10 000 words is highest followed by Appeals to Shared Knowledge Personal Asides Reader Mentions and Questions The distributions of five engagement markers are significantly different within each section X2 109 466 df 4 p 001 X2 268 079 df 3 p 001 X2 234 765 df 4 p 001 X2 600 722 df 4 p 001 A significant difference is found in the overall distribution of five engagement markers among the four sections X2 102 552 df 4 p 001 Meanwhile this study offers suggestions for the teaching of reader engagement in academic writin