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Acylboronate esters/trifluoroborates represent an elusive class of boronates that are of increasing interest for both fundamental study as well as applications at the interface of chemistry and biology. Their preparation has been limited by the use of strongly basic anions, often introduced in multistep reactions. Herein, we demonstrate the facile preparation of acylboronate N-methyliminodiacetyl (MIDA) esters from alkenyl-2-boronate esters through mild dihydroxylation and meta-periodate cleavage. Given the well-known functional-group tolerance of this mild reaction sequence and the availability of alkenyl-2-boronates, this method should greatly increase access to acylboronate MIDA esters. [ABSTRACT FROM AUTHOR]

Light olefins are abundantly manufactured in the petroleum industry and thus represent ideal starting materials for modern chemical synthesis. Selective and divergent transformations of feedstock light olefins to value‐added chemicals are highly sought‐after but remain challenging. Herein we report an exceptionally regioselective carbonickelation of light alkenes followed by in situ trapping with three types of nucleophiles, namely a reductant, base, or Grignard reagent. This protocol enables efficient 1,2‐hydrofunctionalization, dicarbofunctionalization, and branched‐selective Heck‐type cross‐coupling of light alkenes with aryl and alkenyl reagents to streamline access to diverse alkyl arenes and complex alkenes. Harnessing bulky N‐heterocyclic carbene ligands with acenaphthyl backbones for nickel catalysts is crucial to attain high reactivity and selectivity. This strategy provides a rare, modular, and divergent platform for upgrading feedstock alkenes and is expected to find broad applications in medicinal chemistry and industrial processes. [ABSTRACT FROM AUTHOR]

A convenient one‐step synthesis of β‐aminocyclobutane monoesters starting from commercially available reagents is reported. The obtained strained rings undergo (4+2) dearomative annulation with indole partners using silylium catalysis. This organocatalyzed annulation provided tricyclic indolines with four new stereocenters in up to quantitative yield and >95 : 5 diastereoselectivity and can proceed both intra‐ and intermolecularly. When performed intramolecularly, the tetracyclic structure of either akuamma or malagasy alkaloids was obtained selectively depending on the temperature of the reaction. This divergent outcome could be rationalized based on DFT calculations. [ABSTRACT FROM AUTHOR]

Because C2H4 plays an essential role in the chemical industry, economical and energy‐efficient separation of ethylene (C2H4) from ethane (C2H6) is extremely important. With the exception of energy‐intensive cryogenic distillation, there are few one‐step methods to obtain polymer‐grade (≥99.95 % pure) C2H4 from C2H4/C2H6 mixtures. Here we report a highly stable metal‐organic‐framework (MOF) FJI‐H11‐Me(des) (FJI‐H=Hong's group in Fujian Institute of Research on the Structure of Matter) which features one‐dimensional hexagonal nonpolar pore surfaces constructed by aromatic rings and alkyl groups. This FJI‐H11‐Me(des) adsorbs C2H6 rather than C2H4 between 273 and 303 K. Practical breakthrough experiments with C2H4 containing 1 % C2H6 have shown that FJI‐H11‐Me(des) can realize the acquisition in one‐step of polymer‐grade, 99.95 % pure C2H4 under various conditions including different gas flow rates, temperatures and relative humidity. [ABSTRACT FROM AUTHOR]

Sustainable processes for semi‐hydrogenation of alkynes/alkadienes impurities in alkenes feedstocks are in great demand in industry as the utilization of excessive hydrogen, high temperature and unsatisfactory alkenes selectivity of the current thermo‐catalytic route, however, their development is still challenging. Herein, we innovate a light‐assisted semi‐hydrogenation process in gas‐feed fixed bed reactor, with water as hydrogen atom source by in situ photocatalysis. Using Pd/TiO2 as model catalyst, this process shows an excellent catalytic performance for the semi‐hydrogenation of 1,3‐butadiene, with 100 % of butenes selectivity at ≈99 % of conversion over 180 h of reaction at ambient temperature driven by 66 mW cm−2 of irradiation intensity. This light‐driven, H2‐free, ambient temperature semi‐hydrogenation process, with superior performance to that of thermocatalytic route, shows attractive to bring an evolution in industrial hydrogenation technology to an economical and safe way. [ABSTRACT FROM AUTHOR]

Azepanes are important seven‐membered heterocycles, which are present in numerous natural and synthetic compounds. However, the development of convergent synthetic methods to access them remains challenging. Herein, we report the Lewis acid catalyzed (4+3) annulative addition of aryl and amino donor‐acceptor cyclopropanes with 2‐aza‐1,3‐dienes. Densely substituted azepane derivatives were obtained in good to excellent yields and with high diastereoselectivity. The reaction occurred under mild conditions with ytterbium triflate as the catalyst. The use of copper triflate with a trisoxazoline (Tox) ligand led to an enantioselective transformation. The obtained cycloadducts were convenient substrates for a series of further modifications, showing the synthetic utility of these compounds. [ABSTRACT FROM AUTHOR]

The fungal natural product CJ‐12662 is a structurally complex terpene–amino acid hybrid, and is a potent anthelmintic compound. The biosynthetic pathway of CJ‐12662 is elucidated based on metabolite analysis from heterologous expression. We demonstrate the terpene portion is derived from successive P450‐catalyzed oxidations of amorpha‐4,11‐diene, while three flavin‐dependent enzymes are involved in morphing the esterified tryptophan into a chlorinated pyrrolobenzoxazine, utilizing a cascaded [1,2]‐Meisenheimer rearrangement. [ABSTRACT FROM AUTHOR]

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For the separation of ethane from ethylene, it remains challenging to target both high C2H6 adsorption and selectivity in a C2H6‐selective material. Herein, we report a reversible solid‐state transformation in a labile hydrogen‐bonded organic framework to generate a new rod‐packing desolvated framework (ZJU‐HOF‐1) with suitable cavity spaces and functional surfaces to optimally interact with C2H6. ZJU‐HOF‐1 thus exhibits simultaneously high C2H6 uptake (88 cm3 g−1 at 0.5 bar and 298 K) and C2H6/C2H4 selectivity (2.25), which are significantly higher than those of most top‐performing materials. Theoretical calculations revealed that the cage‐like cavities and functional sites synergistically "match" better with C2H6 to provide stronger multipoint interactions with C2H6 than C2H4. In combination with its high stability and ultralow water uptake, this material can efficiently capture C2H6 from 50/50 C2H6/C2H4 mixtures in ambient conditions under 60 % RH, providing a record polymer‐grade C2H4 productivity of 0.98 mmol g−1. [ABSTRACT FROM AUTHOR]

Despite much intense investigation on the C2H2/CO2 separation, the trade‐off between the adsorption capacity and separation selectivity is still tricky. To overcome the dilemma, we have rationally synthesized an ultra‐stable fluorinated hybrid porous material SIFSIX‐Cu‐TPA with the ith‐d topology. Completely differing from the famous pillar‐layer fluorinated materials, SIFSIX‐Cu‐TPA possesses a unique pillar‐cage structure, in which the SiF62− anions cross‐link two adjacent metal nodes as pillars to stabilize the three‐dimensional framework constructed by icosahedral and tetrahedral cages. As anticipated, SIFSIX‐Cu‐TPA has high BET surface area (1330 m2 g−1) as well as high C2H2 uptake (185 cm3 g−1 at 298 K and 1 bar). At the same time, due to the obvious difference in the adsorption performance of CO2 and C2H2 especially in the low pressure area, SIFSIX‐Cu‐TPA also exhibits an excellent C2H2/CO2 separation performance (breakthrough time up to 68 min g−1 at 298 K and 1 bar). [ABSTRACT FROM AUTHOR]

Mild oxetane opening by soft carbon nucleophiles has been developed for efficient C−C bond formation. In the presence of LiNTf2 or TBSNTf2 as catalyst, silyl ketene acetals were found to be effective nucleophiles to generate a wide range of highly oxygenated molecules, which are key substructure in natural products like polyketides. Furthermore, intramolecular oxetane opening by a styrene‐based carbon nucleophile via a Prins‐type process was also achieved with Sc(OTf)3 as catalyst, leading to efficient formation of the useful 2,3‐dihydrobenzo[b]oxepine skeleton. [ABSTRACT FROM AUTHOR]

The development of catalysts that can operate under exceptionally harsh and unconventional conditions is of critical importance for the transition of the energy and chemicals industries to low‐emission and renewable chemical feedstocks. In this review we will highlight materials and more specifically metal‐containing zeolite catalysts that have been tested under harsh reaction conditions such as high temperature light alkane conversion and biomass valorization. Particular attention will be given to studies that explore the stability and recyclability of metal‐containing zeolite catalysts operating in continuous modes. Metal‐containing zeolites are considered as an important class of catalysts operating outside the comfort zone of current heterogeneous catalytic reactions in both gas and liquid phase reactions. The relationship between the properties of the metal‐containing zeolite and catalytic performance will be explored. [ABSTRACT FROM AUTHOR]

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Abstract: Ferrierite zeolites with nanosized crystals and external surface areas higher than 250 m2 g−1 have been prepared at relatively low synthesis temperature (120 °C) by means of the collaborative effect of two organic structure directing agents (OSDA). In this way, hierarchical porosity is achieved without the use of post‐synthesis treatments that usually involve leaching of T atoms and solid loss. Adjusting the synthesis conditions it is possible to decrease the crystallite size in the directions of the 8‐ and 10‐ring channels, [010] and [001] respectively, reducing their average pore length to 10–30 nm and increasing the number of pores accessible. The small crystal size of the nano‐ferrierites results in an improved accessibility of reactants to the catalytic active centers and enhanced product diffusion, leading to higher conversion and selectivity with lower deactivation rates for the oligomerization of 1‐pentene into longer‐chain olefins. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report on a bistable MEMS device actuated by spin-crossover molecules. The device consists of a freestanding silicon microcantilever with an integrated piezoresistive detection system, which was coated with a 140 nm thick film of the [Fe(HB(tz)3)2] (tz=1,2,4-triazol-1-yl) molecular spin-crossover complex. Switching from the low-spin to the high-spin state of the ferrous ions at 338 K led to a reversible upward bending of the cantilever in agreement with the change in the lattice parameters of the complex. The strong mechanical coupling was also evidenced by the decrease of approximately 66 Hz in the resonance frequency in the high-spin state as well as by the drop in the quality factor around the spin transition. [ABSTRACT FROM AUTHOR]

Computational analysis shows that the enantioselectivity of asymmetric Lewis-acid organocatalysis of the Diels-Alder cycloaddition of cyclopentadiene to cinnamates arises from stacking interactions that favor the addition of the diene to the more hindered face of the dienophile, while electrostatic interactions control the diastereoselectivity by selectively stabilizing the endo transition state. These results not only explain the stereoselectivity of these silylium-ion-ACDC reactions but should also guide the development of more effective ion-pairing asymmetric organocatalysts. [ABSTRACT FROM AUTHOR]

Despite the rapid development of frustrated Lewis pair (FLP) chemistry over the last ten years, its application in catalytic hydrogenations remains dependent on a narrow family of structurally similar early main-group Lewis acids (LAs), inevitably placing limitations on reactivity, sensitivity and substrate scope. Herein we describe the FLP-mediated H2 activation and catalytic hydrogenation activity of the alternative LA iPr3SnOTf, which acts as a surrogate for the trialkylstannylium ion iPr3Sn+, and is rapidly and easily prepared from simple, inexpensive starting materials. This highly thermally robust LA is found to be competent in the hydrogenation of a number of different unsaturated functional groups (which is unique to date for main-group FLP LAs not based on boron), and also displays a remarkable tolerance to moisture. [ABSTRACT FROM AUTHOR]

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)