A convenient One-Pot Synthesis of an Unsymmetrical Propane-1,3-diamine BRL 61010A

The one-pot condensation of N-methylhomoveratrylamine with acrolein followed by in situ reductive amination with 3,4-dimethoxyaniline to give an unsymmetrical propane 1,3-diamine in excellent yield is described.     

Copper activation of boronic acids: factors affecting reactivity

The generation of nucleophiles from the combination of aryl boronic acids and catalytic amounts of copper salt allows a reactivity distinct from other organometallic species, such as organolithiums or Grignard reagents. Here we examine how the electronic and steric properties of the boronic acid affect the formation of active nucleophiles and their subsequent reactivity with iminium‐type compounds, showing that electron‐rich substrates display reduced reactivity. Copyright © 2014 John Wiley & Sons, Ltd.     

To Sandwich Technetium: Highly Functionalized Bis-Arene Complexes [99mTc(η6-arene)2]+ Directly from Water and [99mTcO4]−

The labeling of (bio)molecules with metallic radionuclides such as ^99mTc demands conjugated, multidentate chelators. However, this is not always necessary since phenyl rings can directly serve as integrated, organometallic ligands. Bis-arene sandwich complexes are generally prepared by the Fischer–Hafner reaction. In extension of this, we show that [^99mTc(η⁶-C₆R₆)₂]⁺-type complexes are directly accessible from water and [^99mTcO₄]⁻, even using arenes incompatible with Fischer–Hafner conditions. To unambiguously confirm the nature of these unprecedented ^99mTc complexes, their rhenium homologous have been prepared by substituting naphthalene ligands in [Re(η⁶-C₁₀H₈)₂]⁺ with the corresponding phenyl groups. The ease with which highly stable [^99mTc(η⁶-C₆R₆)₂]⁺ complexes are formed under standard labeling conditions enables a multitude of new potential imaging agents based on commercial pharmaceuticals or lead structures.     

Disappearing Polymorphs in Metal–Organic Framework Chemistry: Unexpected Stabilization of a Layered Polymorph over an Interpenetrated Three-Dimensional Structure in Mercury Imidazolate

The “disappearing polymorph” phenomenon is well established in organic solids, and has had a profound effect in pharmaceutical materials science. The first example of this effect in metal-containing systems in general, and in coordination-network solids in particular, is here reported. Specifically, attempts to mechanochemically synthesize a known interpenetrated diamondoid (dia) mercury(II) imidazolate metal–organic framework (MOF) yielded a novel, more stable polymorph based on square-grid (sql) layers. Simultaneously, the dia-form was found to be highly elusive, observed only as a short-lived intermediate in monitoring solvent-free synthesis and not at all from solution. The destabilization of a dense dia-framework relative to a lower dimensionality one is in contrast to the behavior of other imidazolate MOFs, with periodic density functional theory (DFT) calculations showing that it arises from weak interactions, including structure-stabilizing agostic C−H⋅⋅⋅Hg contacts. While providing a new link between MOFs and crystal engineering of organic solids, these findings highlight a possible role for agostic interactions in directing topology and stability of MOF polymorphs.     

Asymmetric Wacker-Type Oxyallenylation and Azaallenylation of Cyclic Alkenes

Palladium-catalyzed three-component carboetherification of cyclic alkenes proceeded to give trans adducts exclusively with excellent enantioselectivity through a Wacker-type pathway. The reaction is also applicable to other oxygen nucleophiles, such as water, phenols, and carboxylic acids, as well as some electron-poor aryl amines.     

In the footsteps of Euler and MacMahon: combinatorics,the mathematics that counts

This article is based on my presidential address, given at the BSHM Christmas meeting on 7 December 2013. It features the history of combinatorics, a much neglected area, with particular reference to the work of two mathematicians who have always interested me—Leonhard Euler and Major Percy MacMahon—and with further contributions by Arthur Cayley (on trees) and G H Hardy and S Ramanujan (on partitions).