Junghwan Do

Bio: Junghwan Do is an academic researcher from Konkuk University. The author has contributed to research in topics: Enantioselective synthesis & Ethylenediamine. The author has an hindex of 8, co-authored 20 publications receiving 135 citations.

Asymmetric synthesis of trans-2,3-disubstituted indoline derivatives.

Abstract: A novel method for asymmetric synthesis of trans-2,3-disubstituted indolines has been developed. The strategy involves the (−)-sparteine-mediated electrophilic substitution of 2-benzyl N-pivaloylaniline with aromatic or α,β-unsaturated aldehydes and subsequent intramolecular nucleophilic substitution. The simple protocol for two-step process can produce highly enantioenriched indolines 3a–o up to 98:2 er.

Progress in the Chemistry of Tetrahydroquinolines.

Abstract: Tetrahydroquinoline is one of the most important simple nitrogen heterocycles, being widespread in nature and present in a broad variety of pharmacologically active compounds. This Review summarizes the progress achieved in the chemistry of tetrahydroquinolines, with emphasis on their synthesis, during the period from mid-2010 to early 2018.

Pillar-layered MOFs: Functionality, Interpenetration, Flexibility and Applications

Abstract: Pillar-layered metal–organic frameworks (MOFs) are among the most interesting research areas in crystalline materials. Due to the great number of reports related to pillar-layered MOFs, investigating their structural diversity, properties and applicability as multi-donor porous frameworks is of great interest. Modifying pillar moieties as a third building block of pillar-layered MOFs, together with metal nodes and oxygen donor linkers, can enhance control of the structure assembly, leading to specific properties of the obtained structures. Although the past decade has witnessed remarkable advances in this research area, pillar-layered MOFs have not been reviewed as an independent subject to date. Therefore, a review summarizing their performance is greatly needed. This review covers issues related to pillar-layered MOFs, including their structural properties, synthesis, stability, diversity of linkers, and improved applicability. Finally, pillar linkers are studied separately according to their diverse donor atoms and functional groups.

A review of the structural architecture of tellurium oxycompounds

Abstract: Relative to its extremely low abundance in the Earth's crust, tellurium is the most mineralogically diverse chemical element, with over 160 mineral species known that contain essential Te, many of them with unique crystal structures. We review the crystal structures of 703 tellurium oxysalts for which good refinements exist, including 55 that are known to occur as minerals. The dataset is restricted to compounds where oxygen is the only ligand that is strongly bound to Te, but most of the Periodic Table is represented in the compounds that are reviewed. The dataset contains 375 structures that contain only Te cations and 302 with only Te, with 26 of the compounds containing Te in both valence states. Te was almost exclusively in rather regular octahedral coordination by oxygen ligands, with only two instances each of 4- and 5-coordination. Conversely, the lone-pair cation Te displayed irregular coordination, with a broad range of coordination numbers and bond distances. A threshold was applied for Te-O links of ~2.45 A or 0.3 valence units with some flexibility, as a criterion to define strongly bound Te-O polymers and larger structural units. Using this criterion, Te cations display one-sided 3-, 4- or 5-coordination by oxygen (with rare examples of coordination numbers 2 and 6). For both valence states of Te, examples are known of TeO complexes which are monomeric (m = 1; neso), noncyclic finite oligomers (soro), rings (cyclo), infinite chains (ino), layers (phyllo) and frameworks (tecto tellurates). There is a clear analogy to the polymerization classes that are known for silicate anions, but the behaviour of Te is much richer than that of Si for several reasons: (1) the existence of two cationic valence states for Te; (2) the occurrence of multiple coordination numbers; (3) the possibility of edge-sharing by TeO polyhedra; (4) the possibility for oxygen ligands to be 3-coordinated by Te; and (5) the occurrence of TeO polymers that are cationic, as well as neutral or anionic. While most compounds contain only one or two symmetrically distinct types of Te atom, Pauling's Fifth Rule is frequently violated, and stoichiometrically simple compounds such as CaTeO can have polymorphs with up to 18 distinct Te sites. There is a tendency for local symmetry features such as the threefold axis of a TeO octahedron or the acentric symmetry of a TeO polyhedron to be inherited by the host structure; the latter in particular can lead to useful physical properties such as nonlinear optical behaviour. We develop for the first time a hierarchical taxonomy of Te-oxysalt structures, based upon (1) valence state of Te; (2) polymerization state of TeO complexes; (3) polymerization state of larger strongly-bound structural units that include non-Te cations. Structures are readily located and compared within this classification.

Highly Diastereo- and Enantioselective CuH-Catalyzed Synthesis of 2,3-Disubstituted Indolines

Abstract: A diastereo- and enantioselective CuH-catalyzed method for the preparation of highly functionalized indolines is reported. The mild reaction conditions and high degree of functional group compatibility as demonstrated with substrates bearing heterocycles, olefins, and substituted aromatic groups, renders this technique highly valuable for the synthesis of a variety of cis-2,3-disubstituted indolines in high yield and enantioeselectivity.