Metrics & MoreArticle Recommendations CONSPECTUS: Recently, alkene dicarbofunctionalization, i.e., the powerful organic synthesis method of alkene difunctionalization with two carbon sources, emerged as a formidable reaction with immense promise to synthesize complex molecules expeditiously from simple chemicals. This reaction is generally achieved with transition metals (TMs) through interception by carbon sources of an alkylmetal [β-H−C(sp 3 )−[M]] species, a key intermediate prone to undergo rapid β-H elimination. Related prior reports, since Paolo Chiusoli and Catellani's work in 1982 [Tetrahedron Lett. 1982, 23, 4517], have used bicyclic and disubstituted terminal alkenes, wherein β-H elimination is avoided by geometric restriction or complete lack of β-H's. With reasoning that β-H−C(sp 3 )− [M] intermediates could be rendered amenable to interception with the use of first row late TMs and formation of coordinationassisted transient metallacycles, these two strategies were implemented to address the β-H elimination problem in alkene dicarbofunctionalization reactions. Because first row late TMs catalyze C(sp 3 )−C(sp 3 ) coupling, Cu and Ni were anticipated to impart sufficient stability to β-H− C(sp 3 )−[M] intermediates, generated catalytically upon alkene carbometalation, for their subsequent interception by carbon electrophiles/nucleophiles in three-component reactions. Additionally, such an innate property could enable alkene difunctionalization with carbon coupling partners through entropically driven cyclization/coupling reactions. The cyclometalation concept to stabilize intractable β-H−C(sp 3 )−[M] intermediates was hypothesized when three-component reactions were performed. The idea of cyclometalation to curtail β-H elimination is founded upon Whitesides's [J. Am. Chem. Soc. 1976, 98, 6521] observation that metallacycles undergo β-H elimination much slower than acyclic alkylmetals. In this Account, examples of alkene dicarbofunctionalization reactions demonstrate that Cu and Ni catalysts could enable cyclization/coupling of alkenylzinc reagents, alkyl halides, and aryl halides to afford complex carbo-and heterocycles. In addition, forming coordination-assisted transient nickellacycles enabled regioselective performance of three-component dicarbofunctionalization of various alkenyl compounds. In situ reaction of [M]-H with alkenes generated after β-H elimination induced an unprecedented metallacycle contraction process, in which six-membered metal-containing rings shrank to five-membered cycles, allowing creation of new carbon−carbon bonds at allylic (1,3) positions. Applications of these regioselective alkene dicarbofunctionalization reactions are discussed.

We disclose a Ni-catalyzed vicinal difunctionalization of alkenes with benzyl halides and alkylzinc reagents, which produces products with two new alkyl–alkyl bonds. This alkene dialkylation is effective in combining secondary benzyl halides and secondary alkylzinc reagents with internal alkenes, which furnishes products with three contiguous all-carbon secondary stereocenters. The products can be readily elaborated to access complex tetralene, benzosuberene, and bicyclodecene cores. The reaction also features as the most efficient alkene difunctionalization process to date with catalyst loadings down to 500 ppm and the catalytic turnover number (TON) and turnover frequency (TOF) registering up to 2 × 103 and 165 h–1 at rt, respectively.

Chemical analysis of the organic components in beer has applications to quality control, authenticity and improvements to the flavor characteristics and brewing process. This study aims to show the complementary nature of two instrumental techniques which, in combination, can identify and quantify a number of organic components in a beer sample. Nuclear Magnetic Resonance (NMR) was used to provide concentrations of 26 different organic compounds including alcohols, organic acids, carbohydrates, and amino acids. Calorie content was also estimated for the samples. NMR data for ethanol concentrations were validated by comparison to a Fourier Transform Infrared Spectrometry (FTIR) method. Headspace Solid-Phase Microextraction (SPME) Gas Chromatography Mass Spectrometry (GCMS) was used to identify a range of volatile compounds such as alcohols, esters and hop-derived aroma compounds. A simple and inexpensive conversion of a Gas Chromatography Flame Ionization Detector (GC FID) instrument to allow the use of Solid-Phase Microextraction was found to be useful for the quantification of volatile esters.

Background Significant progress has been made in advancing and standardizing tools for human genomic and biomedical research. Yet, the field of next-generation sequencing (NGS) analysis for microorganisms (including multiple pathogens) remains fragmented, lacks accessible and reusable tools, is hindered by local computational resource limitations, and does not offer widely accepted standards. One such “problem areas” is the analysis of Transposon Insertion Sequencing (TIS) data. TIS allows probing of almost the entire genome of a microorganism by introducing random insertions of transposon-derived constructs. The impact of the insertions on the survival and growth under specific conditions provides precise information about genes affecting specific phenotypic characteristics. A wide array of tools has been developed to analyze TIS data. Among the variety of options available, it is often difficult to identify which one can provide a reliable and reproducible analysis. Results Here we sought to understand the challenges and propose reliable practices for the analysis of TIS experiments. Using data from two recent TIS studies, we have developed a series of workflows that include multiple tools for data de-multiplexing, promoter sequence identification, transposon flank alignment, and read count repartition across the genome. Particular attention was paid to quality control procedures, such as determining the optimal tool parameters for the analysis and removal of contamination. Conclusions Our work provides an assessment of the currently available tools for TIS data analysis. It offers ready to use workflows that can be invoked by anyone in the world using our public Galaxy platform (https://usegalaxy.org). To lower the entry barriers, we have also developed interactive tutorials explaining details of TIS data analysis procedures at https://bit.ly/gxy-tis.

We report aN i-catalyzed regioselective arylbenzylation of alkenylarenes with benzyl halides and arylzinc reagents.T he reaction furnishes differently substituted 1,1,3triarylpropyl structures that are reminiscent of the cores of oligoresveratrol natural products.The reaction is also compatible for the coupling of internal alkenes,s econdary benzyl halides and variously substituted arylzinc reagents.K inetic studies reveal that the reaction proceeds with ar ate-limiting single-electron-transfer process and is autocatalyzed by in-situgenerated ZnX 2 .T he reaction rate is amplified by af actor of three through autocatalysis upon addition of ZnX 2 .Scheme 1. Common alkene dicarbofunctionalization reactions.Scheme 2. Natural products bearing diarylalkyl and triarylalkyl cores.