Highly Enantioselective Conjugate Additions of Phosphites to α,β‐Unsaturated N‐Acylpyrroles and Imines: A Practical Approach to Enantiomerically Enriched Amino Phosphonates

The first highly enantioselective phosphonylation of α,β‐unsaturated N‐acylpyrroles has been developed. Excellent yields (91–99 %) and enantioselectivities (up to >99 % enantiomeric excess (ee)) were observed for a broad spectrum of both phosphites and N‐acylpyrroles under mild conditions. In particular, when diethyl phosphite was employed to test the scope of the N‐acylpyrroles, almost optically pure products (98 to >99 % ee) were obtained for 20 examples of N‐acylpyrroles. Moreover, optically pure α‐substituted β‐ or γ‐amino phosphonates can be obtained by several simple transformations of the pyrrolyl phosphonates. The versatility of the N‐acylpyrrole moiety makes the phosphorus adducts powerful chiral building blocks that enable the synthesis of various phosphonate‐containing compounds. Finally, the present strategy can also be applied to the asymmetric hydrophosphonylation of N‐acylimines with high enantioselectivities (93 to >99 % ee).     

Hydrothermal Synthesis,Crystal Structure and Characterizations of Two New Manganese(II) Phosphonates with a 3D Framework Structure

Two new manganese(II) phosphonates, (NH₄)Mn_2.5[(O₃PCH(OH)CO₂)₂(H₂O)] ( 1 ) and [NH₃(CH₂)₄NH₃]_0.5Mn_2.5[(O₃PCH(OH)CO₂)₂(H₂O)] ( 2 ) have been synthesized under hydrothermal conditions and structurally characterized by single‐crystal X‐ray diffraction as well as with infrared spectroscopy, elemental analysis and thermogravimetric analysis. The two isomorphous compounds feature a 3D framework structure. The Mn(1)O₆ and Mn(3)O₅ polyhedra are bridged by the CPO₃ tetraheda into a Mn^II phosphonate layer in ac‐plane. Mn(2)O₆ polyhedra are linked to each other by CPO₃ tetraheda to form infinite chains, which are connected to layers by carboxylate groups to form a 3D framework structure with channels along the a‐ and c‐axis, respectively. The NH₄⁺ ions or protonated 1, 4‐butylenediamine cations are located inside the channels along the a axis.     

Conformational analysis and regioisomerism of mono- and diadducts of O,O-diisopropyl isoxazolinophosphonate with C60

Theoretically, cycloaddition of two molecules of phosphorylated nitrile oxide to C₆₀ can give rise to 22 regioisomers. A simple convenient nomenclature was proposed for their classification based on the well-known Hirsh nomenclature. A combination of HPLC, semiempirical quantum-chemical PM3 calculations, and the dipole moment method demonstrated that the equatorial, trans-4(tt), and trans-3(tt) adducts are most probable.     

POLYHEDRAL METALLOPHOSPHONATES AND -SILICATES: SYNTHESIS,FUNCTIONALIZATION, AND TRANSFORMATIONS

We synthesized molecular cyclic and polyhedral precursors to aluminophosphate and silicate materials and studied their substitution and nonhydrolytic sol-gel reactions.     

PHOSPHONYLATION BY A SPIROPHOSPHORANE: APPLICATION OF THE RIBOZYME CHEMISTRY IN THE BIOORGANIC SYNTHESIS

The phosphonylation by oxirane/phosphorous acid is characterized by formation of spirophosphorane, which provides the active intermediate in the reaction, β-hydroxyalkyl alkylene phosphite. Here, we demonstrate that a well-known and readily accessible spirophosphorane, 2λ⁵-2,2′spirobi[1,3,2-benzodioxaphosphole] can be used as convenient and effective phosphonylating agent in similar reaction. The easily detectable primary 3-phenylpropyl H-phosphonate, as well as 5′-O-tritylthymidyl, 4-N-benzoyl-5′-O-trityl-deoxycytidyl, 5′-O-trityl-deoxycytidyl, 6-N-benzoyl-5′-O-trityl- deoxyadenosyl 5′-O-trityluridyl, and 2′,3′-isopropylidene-uridyl H-phosphonates were prepared using a simple and straightforward procedure. Our results provide an interesting example of the potential and the limitations of a synthetic approach utilising reaction of leaving of diol system.     

REDUCTION OF TERMINAL ORGANYLCHALCOGENO PHOSPHONATES AS A WAY TO PREPARE PRIMARY ORGANYLCHALCOGENO PHOSPHINES

2-Organylseleno(telluro)ethyl phosphines and 4-organylthio(seleno (telluro))butyl phosphines were prepared by reduction of diethyl 2-organylseleno(telluro)ethyl phosphonates and diethyl 4-organylthio(seleno(telluro)) butyl phosphonates with lithium aluminium hydride in diethyl ether. ¹H and ³¹P NMR spectra as well as mass spectra of the resulting phosphines were considered. Their stability in regard to the oxidation by oxygen was discussed.     

Polyethylene Glycol–Promoted Dialkyl,Aryl/Heteroaryl Phosphonates

A new, straightforward polyethylene glycol–promoted method for Michaelis–Arbuzov rearrangement has been described.     

异金属膦酸铀的合成、晶体结构和荧光性质

构建异金属膦酸铀仍然具有挑战性。在本工作中,从苯磺酰甲基膦酸二乙酯(Et₂L)出发,成功合成了一系列同构的异金属膦酸铀化合物[UO₂M (L)₂(H₂O)₄],其中M=Mn (1)、Co (2)、Ni (3)、Zn (4)、Cd (5)。晶体结构研究表明,磺酰基团没有与金属离子配位,而膦酸基团完全去质子化,连接2个铀酰离子和1个过渡金属离子,形成了二维层状晶体结构。荧光研究表明,在Mn (Ⅱ)、Co (Ⅱ)和Ni (Ⅱ)离子存在时,铀酰离子的特征荧光发射被猝灭,而在Zn (Ⅱ)和Cd (Ⅱ)离子存在时,显示出强的特征荧光发射。     

Water Oxidation by Ruthenium Complexes Incorporating Multifunctional Bipyridyl Diphosphonate Ligands

We describe herein the synthesis and characterization of ruthenium complexes with multifunctional bipyridyl diphosphonate ligands as well as initial water oxidation studies. In these complexes, the phosphonate groups provide redox‐potential leveling through charge compensation and σ donation to allow facile access to high oxidation states. These complexes display unique pH‐dependent electrochemistry associated with deprotonation of the phosphonic acid groups. The position of these groups allows them to shuttle protons in and out of the catalytic site and reduce activation barriers. A mechanism for water oxidation by these catalysts is proposed on the basis of experimental results and DFT calculations. The unprecedented attack of water at a neutral six‐coordinate [Ru^IV] center to yield an anionic seven‐coordinate [Ru^IV?OH]^? intermediate is one of the key steps of a single‐site mechanism in which all species are anionic or neutral. These complexes are among the fastest single‐site catalysts reported to date.