Organocatalytic Atroposelective Construction of Axially Chiral Nonsymmetric Biaryltriols and Their Applications on Asymmetric Synthesis and Heavy Metal Ion Detection

An organocatalytic methodology toward the atroposelective construction of axially chiral nonsymmetric biaryltriols has been successfully developed. Quinine-derived thiourea-catalyzed intramolecular reaction through VQM (vinylidene ortho-quinone methides) intermediate enabled efficient access to...

Amylomaltases in Extremophilic Microorganisms

Amylomaltases (4-α-glucanotransferases, E.C. 2.4.1.25) are enzymes which can perform a double-step catalytic process, resulting in a transglycosylation reaction. They hydrolyse glucosidic bonds of α-1,4′-d-glucans and transfer the glucan portion with the newly available anomeric carbon to the 4′-position of an α-1,4′-d-glucan acceptor. The intramolecular reaction produces a cyclic α-1,4′-glucan. Amylomaltases can be found only in prokaryotes, where they are involved in glycogen degradation and maltose metabolism. These enzymes are being studied for possible biotechnological applications, such as the production of (i) sugar substitutes; (ii) cycloamyloses (molecules larger than cyclodextrins), which could potentially be useful as carriers and encapsulating agents for hydrophobic molecules and also as effective protein chaperons; and (iii) thermoreversible starch gels, which could be used as non-animal gelatin substitutes. Extremophilic prokaryotes have been investigated for the identification of amylomaltases to be used in the starch modifying processes, which require high temperatures or extreme conditions. The aim of this article is to present an updated overview of studies on amylomaltases from extremophilic Bacteria and Archaea, including data about their distribution, activity, potential industrial application and structure.

Tandem diaza-Cope rearrangement polymerization: turning intramolecular reaction into powerful polymerization to give enantiopure materials for Zn2+ sensors

Herein, we report a new tandem diaza-Cope rearrangement polymerization synthesizing enantiopure polymers with defect-free C–C bond formation. Furthermore, these polymers can be applied as high-performance turn-on Zn2+ sensors.

Insight into intramolecular chemical structure modifications by on-surface reaction using photoemission tomography

We present the first evidence of an on-surface intramolecular reaction detected via an imaging method based on photoemission.

SYBR Green I promotes melamine binding to poly-thymine DNA and FRET-based ratiometric sensing

Using SYBR Green I for DNA melting experiments, polythymine DNA binding to melamine was found to be an intramolecular reaction, allowing the design of a FRET-based biosensor and its sensitivity was enhanced by SYBR Green I.

Ni-catalyzed non-activated C-S bond cleavage at ambient temperature for the synthesis of sulfur-containing polycyclic compounds

A Ni-catalyzed intramolecular reaction of diarylthioether-tethered 1,8-diynes gave sulfur-containing tetracyclic compounds at ambient temperature. The transformation was initiated by non-activated sp2 C-S bond cleavage along with consecutive alkyne insertions. A...

The intramolecular reaction of acetophenone N-tosylhydrazone and vinyl: Brønsted acid-promoted cationic cyclization toward polysubstituted indenes

In the presence of TsNHNH2, a Brønsted acid-promoted intramolecular cyclization of o-(1-arylvinyl) acetophenone derivatives was developed, leading to polysubstituted indenes with complexity and diversity in moderate to excellent yields.

Decarboxylative Umpolung Synthesis of Amines from Carbonyl Compounds

2-Azaallyl anions are valuable intermediates which have versatile applications in functionalization with various electrophiles. Decarboxylation of the imines formed from aromatic aldehydes and α,α-diphenylglycine provides an interesting and efficient way to generate delocalized 2-azaallyl anions, which display high reactivity toward different electrophiles with excellent regioselectivity at the diphenylketimino aryl carbon of the 2-azaallyl anions. The transformation produces various amines in good yields under very mild conditions. This Synpacts article highlights the recent advances on the decarboxylative umpolung synthesis of amines from carbonyl compounds.1 Introduction2 Decarboxylative Umpolung Reactions of Carbonyl Compounds with Different Electrophiles2.1 Reaction with π-Allyl–Pd(II) Species2.2 Reaction with Morita–Baylis–Hillman Adducts2.3 Reaction with Imines2.3.1 Intermolecular Reaction with N-Ts Imines2.3.2 Intramolecular Reaction with Chiral N-tert-Butanesulfinyl Imines2.4 Reaction with Aldehydes and Ketones3 Decarboxylative Umpolung Reaction of α,β-Unsaturated Aldehydes with Aldehydes4 Conclusion