Kinetic Resolution of Unsaturated Amides in a Chlorocyclization Reaction: Concomitant Enantiomer Differentiation and Face Selective Alkene Chlorination by a Single Catalyst

The first example of a kinetic resolution via chlorofunctionalization of olefins is reported. The enantiomers of racemic unsaturated amides were found to have different hydrogen-bonding affinities for chiral Lewis bases in numerous solvents. This interaction was exploited in developing a kinetic resolution of racemic unsaturated amides via halocyclization. The same catalyst serves to both “sense chirality” in the substrate as well as mediate a highly face-selective chlorine delivery onto the olefin functionality, resulting in stereotriad products in up to 99:1 <i>dr</i> and up to 98.5:1.5 <i>er</i>. The selectivity factors were typically greater than 50 to allow for the simultaneous synthesis of both the products and unreacted substrates in highly enantioenriched form at yields approaching 50%. The reaction employs catalytic amounts (≤0.50 mol %) of a commercially available and recyclable organocatalyst

Kinetic Resolution of Unsaturated Amides in a Chlorocyclization Reaction: Concomitant Enantiomer Differentiation and Face Selective Alkene Chlorination by a Single Catalyst

The first example of a kinetic resolution via chlorofunctionalization of olefins is reported. The enantiomers of racemic unsaturated amides were found to have different hydrogen-bonding affinities for chiral Lewis bases in numerous solvents. This interaction was exploited in developing a kinetic resolution of racemic unsaturated amides via halocyclization. The same catalyst serves to both “sense chirality” in the substrate as well as mediate a highly face-selective chlorine delivery onto the olefin functionality, resulting in stereotriad products in up to 99:1 <i>dr</i> and up to 98.5:1.5 <i>er</i>. The selectivity factors were typically greater than 50 to allow for the simultaneous synthesis of both the products and unreacted substrates in highly enantioenriched form at yields approaching 50%. The reaction employs catalytic amounts (≤0.50 mol %) of a commercially available and recyclable organocatalyst

Kinetic Resolution of Unsaturated Amides in a Chlorocyclization Reaction: Concomitant Enantiomer Differentiation and Face Selective Alkene Chlorination by a Single Catalyst

The first example of a kinetic resolution via chlorofunctionalization of olefins is reported. The enantiomers of racemic unsaturated amides were found to have different hydrogen-bonding affinities for chiral Lewis bases in numerous solvents. This interaction was exploited in developing a kinetic resolution of racemic unsaturated amides via halocyclization. The same catalyst serves to both “sense chirality” in the substrate as well as mediate a highly face-selective chlorine delivery onto the olefin functionality, resulting in stereotriad products in up to 99:1 <i>dr</i> and up to 98.5:1.5 <i>er</i>. The selectivity factors were typically greater than 50 to allow for the simultaneous synthesis of both the products and unreacted substrates in highly enantioenriched form at yields approaching 50%. The reaction employs catalytic amounts (≤0.50 mol %) of a commercially available and recyclable organocatalyst

Balancing Energy and Stability of Nitroamino-1,2,4-Oxadiazoles through a Planar Bridge

By integrating two approachesan ethene bridge to enhance safety and planarity to support good densitywe have achieved new high-energy-density materials 4–8. Compounds 4–8 show good detonation performance (Dv = 8037–9305 m s–1 and DP = 24.7–33.4 GPa) and large enthalpies of formation (260.1–1444.9 kJ mol–1). The detonation velocity of compound 8 (9305 ms–1) approaches that of HMX (9320 ms–1), which suggests it is a competitive high-energy-density material

Absolute Configuration for 1,<i>n</i>-Glycols: A Nonempirical Approach to Long-Range Stereochemical Determination

The absolute configurations of 1,<i>n</i>-glycols (<i>n</i> = 2–12, 16) bearing two chiral centers were rapidly determined via exciton-coupled circular dichroism (ECCD) using a tris­(pentafluorophenyl)­porphyrin (TPFP porphyrin) tweezer system in a nonempirical fashion devoid of chemical derivatization. A unique “side-on” approach of the porphyrin tweezer relative to the diol guest molecule is suggested as the mode of complexation

Absolute Configuration for 1,<i>n</i>-Glycols: A Nonempirical Approach to Long-Range Stereochemical Determination

The absolute configurations of 1,<i>n</i>-glycols (<i>n</i> = 2–12, 16) bearing two chiral centers were rapidly determined via exciton-coupled circular dichroism (ECCD) using a tris­(pentafluorophenyl)­porphyrin (TPFP porphyrin) tweezer system in a nonempirical fashion devoid of chemical derivatization. A unique “side-on” approach of the porphyrin tweezer relative to the diol guest molecule is suggested as the mode of complexation

Absolute Configuration for 1,<i>n</i>-Glycols: A Nonempirical Approach to Long-Range Stereochemical Determination

The absolute configurations of 1,<i>n</i>-glycols (<i>n</i> = 2–12, 16) bearing two chiral centers were rapidly determined via exciton-coupled circular dichroism (ECCD) using a tris­(pentafluorophenyl)­porphyrin (TPFP porphyrin) tweezer system in a nonempirical fashion devoid of chemical derivatization. A unique “side-on” approach of the porphyrin tweezer relative to the diol guest molecule is suggested as the mode of complexation

Control of Self-Penetration and Dimensionality in Luminescent Cadmium Succinate Coordination Polymers via Isomeric Dipyridylamide Ligands

Reaction in aqueous solution of cadmium nitrate, succinic acid (H₂suc), and one of four possible isomeric dipyridylamide coligands has afforded a series of two-dimensional (2-D) and three-dimensional (3-D) coordination polymers. All were structurally characterized by single-crystal X-ray diffraction. [Cd­(suc)­(4-pina)]_<i>n</i> (<b>1</b>, 4-pina = 4-pyridylisonicotinamide) displays a 3-D 6-connected self-penetrated 4⁴6¹⁰8 <b>mab</b> topology, while {[Cd­(suc)­(3-pna)]·2.5H₂O}_<i>n</i> (<b>2</b>, 3-pna = 3-pyridylnicotinamide) has a simple 3-D non-interpenetrated 4¹²6³ <b>pcu</b> network. The supramolecular isomer <b>2′</b> has exactly the same stoichiometry and overall <b>pcu</b> topology as <b>2</b> but shows a difference in succinate binding mode. Compounds <b>1</b>, <b>2</b>, and <b>2′</b> all show similar [Cd­(suc)]_<i>n</i> layers with embedded {Cd₂O₂} rhomboid dimers that serve as the 6-connected nodes. {[Cd­(suc)­(4-pna)­(H₂O)]·2H₂O}_<i>n</i> (<b>3</b>, 4-pna = 4-pyridylnicotinamide) manifests an extremely rare 2-D 4-connected 6⁶ layer self-penetrated topology based on cross-pillared [Cd­(suc)]_<i>n</i> helical chains. Slight adjustment of the donor disposition resulted in the formation of the 2-D (4,4) grid coordination polymer {[Cd­(suc)­(3-pina)­(H₂O)]·3.5H₂O}_<i>n</i> (<b>4</b>, 3-pina = 3-pyridylisonicotinamide), which has [Cd­(suc)]_<i>n</i> helical chains similar to those in <b>3</b> but avoids cross-pillaring. Luminescent and thermal properties of these four new materials are discussed

Control of Self-Penetration and Dimensionality in Luminescent Cadmium Succinate Coordination Polymers via Isomeric Dipyridylamide Ligands

Reaction in aqueous solution of cadmium nitrate, succinic acid (H₂suc), and one of four possible isomeric dipyridylamide coligands has afforded a series of two-dimensional (2-D) and three-dimensional (3-D) coordination polymers. All were structurally characterized by single-crystal X-ray diffraction. [Cd­(suc)­(4-pina)]_<i>n</i> (<b>1</b>, 4-pina = 4-pyridylisonicotinamide) displays a 3-D 6-connected self-penetrated 4⁴6¹⁰8 <b>mab</b> topology, while {[Cd­(suc)­(3-pna)]·2.5H₂O}_<i>n</i> (<b>2</b>, 3-pna = 3-pyridylnicotinamide) has a simple 3-D non-interpenetrated 4¹²6³ <b>pcu</b> network. The supramolecular isomer <b>2′</b> has exactly the same stoichiometry and overall <b>pcu</b> topology as <b>2</b> but shows a difference in succinate binding mode. Compounds <b>1</b>, <b>2</b>, and <b>2′</b> all show similar [Cd­(suc)]_<i>n</i> layers with embedded {Cd₂O₂} rhomboid dimers that serve as the 6-connected nodes. {[Cd­(suc)­(4-pna)­(H₂O)]·2H₂O}_<i>n</i> (<b>3</b>, 4-pna = 4-pyridylnicotinamide) manifests an extremely rare 2-D 4-connected 6⁶ layer self-penetrated topology based on cross-pillared [Cd­(suc)]_<i>n</i> helical chains. Slight adjustment of the donor disposition resulted in the formation of the 2-D (4,4) grid coordination polymer {[Cd­(suc)­(3-pina)­(H₂O)]·3.5H₂O}_<i>n</i> (<b>4</b>, 3-pina = 3-pyridylisonicotinamide), which has [Cd­(suc)]_<i>n</i> helical chains similar to those in <b>3</b> but avoids cross-pillaring. Luminescent and thermal properties of these four new materials are discussed

Highly Selective Nitroamino Isomerization Guided by Proton Transport Dynamics: Full-Nitroamino Imidazole[4,5‑<i>d</i>]pyridazine Fused-Ring System

Due to the advantage of the hydrogen bond system formed by nitroamino isomerization, by the calculations of hydrogen transfer in reported nitroamino explosives, the proton transport dynamics was first proposed to predict the nitroamino isomerization of energetic materials. With the calculated results of zero-point energy, the full-nitroamino fused energetic materials, 2,4-nitroamino-7-nitroimino-1,5-dihydro-4H-imidazolo[4,5-d]pyridazine (FNPI-1) and 2,2′,7,7′-tetranitromino-4,4′-azo-imidazolo[4,5-d]pyridazine (FNPI-2) were designed and successfully synthesized. The highly selective nitroamino isomerization of neutral compound FNPI-1 is shown by X-ray diffraction. After the hydrogen transfer occurs, the intermolecular hydrogen bonds will greatly promote tight stacking, which enhances the density and thus a series of comprehensive properties of energetic materials. The theoretical calculations of zero-point energy explain perfectly the selectivity of hydrogen transfer between the nitroamino groups and the fused-ring skeleton for FNPI-1. The hydrogen atom transfer and selective isomerization of nitroamino energetic materials can be accurately predicted following proton transport dynamics, which provides computational bases and new ideas for the efficient design of fully nitroamino-based explosives