[2+2] photocycloaddition of cinnamates, using a previously described cone reactor and a bis‐thiourea catalyst, is greatly accelerated by employing liquid–liquid slug flow. In most cases, a four‐fold acceleration in reaction time was observed with equivalent or superior yields. This approach has enabled significant improvement in the reaction throughput and expansion of the substrate scope to include challenging substrates. It has also enabled, to our knowledge, the first reported direct photodimerization in solution of electron‐rich cinnamamide substrates.

The front cover artwork is provided by the Beeler Research Group in the Department of Chemistry at Boston University. The image depicts a metal halide lamp surrounded by a length of tubing. Inside the tubing is a rendition of a biphasic flow and a simplified depiction of simulated circulation patterns within the slugs. At the top right is a DFT‐optimized model of delta truxinate, highlighting the beauty of the molecules that this flow system can be used to synthesize. Read the full text of the Article at https://doi.org/10.1002/cptc.201800081.

Asymmetric allylic alkylation (AAA) presents an exceptionally powerful and efficient tool for the rapid synthesis of a diverse range of chiral compounds with high yields and excellent levels of enantioselectivity. To support the production of ethyl (R)-1-allyl-2-oxocyclohexane-1-carboxylate 1 on a large scale, a highly practical and economical AAA process is highly desirable. Herein, we report a greatly improved reaction protocol by thorough optimization of the original conditions developed by Trost et al. Multiple reaction parameters including reaction temperature, concentration, stoichiometric amount of TMG (1,1,3,3-tetramethylguanidine), and water are thoroughly investigated. It was determined that the reaction rate was significantly improved in the presence of 2.0 equiv of TMG and an optimal amount of water (Pd:H2O = 1:160) at 10–15 °C. Our efforts led to the design and development of a highly efficient chemical process using [η3-C3H5PdCl]2 as low as 0.025 mol % under solvent-free conditions, enabling facile and robust scaleup in an economical and sustainable fashion on a large scale.

An improved chemical process has been developed for the synthesis of (S,S)-DACH-Ph Trost ligand. The amidation of 2-diphenylphosphinylbenzoic acid and (S,S)-diaminocyclohexane is promoted by stoichiometric CDI and catalytic imidazole hydrochloride. The resulting product, (S,S)-DACH-Ph Trost ligand, is isolated as a white solid in 80% yield with >99% ee by simple filtration without column chromatography. The current facile process is also demonstrated on kilogram scale.

The Front Cover illustrates the application of a biphasic liquid slug flow system for the [2+2] photocycloaddition of cinnamates. This approach has enabled significant improvement of reaction throughput and expansion of the substrate scope compared to the typical monophasic reaction. More information can be found in the Article by R. Telmesani et al. on page 865 in Issue 10, 2018 (DOI: 10.1002/cptc.201800081).