A Neutral Donor-Acceptor p-Stack: Solid-State Structures of 1 : 1 Pyromellitic Diimide-Dialkoxynaphthalene Cocrystals

1997 ◽  
Vol 50 (4) ◽  
pp. 271 ◽  
Author(s):  
Rina Carlini ◽  
Cheng-Lin Fang ◽  
Deborah Herrington ◽  
Kerianne Higgs ◽  
Russell Rodrigo ◽  
...  

Substituted ortho-benzoquinones, generated in situ by hypervalent iodine oxidation of catechols, are intercepted by unsymmetrical dienes to provide Diels-Alder adducts with complete regiospecificity. Catechols with carboxy substituents in the 3 or 4 positions react similarly and the initial adducts decarboxylate to produce 8-substituted or 5-substituted 1,2-dihydroxydihydronaphthalenes respectively, in a one-pot three-step sequence. The reaction has been further adapted to produce naphtho[1,8-bc]furans in a one-pot process; its application towards the synthesis of the tricyclic system of the sesquiterpene nardonoxide is described

1997 ◽  
Vol 50 (5) ◽  
pp. 439 ◽  
Author(s):  
Darren G. Hamilton ◽  
Daniel E. Lynch ◽  
Karl A. Byriel ◽  
Colin H. L. Kennard

Pyromellitic diimide forms orange-coloured cocrystals of 1 : 1 stoichiometry with dialkoxynaphthalene derivatives. The solid-state structures of two examples are presented. The cocrystal formed with 2,6-dimethoxynaphthalene presents vertical stacks of alternating π-rich and π-deficient subunits with the long axes of the respective components approximately parallel. Investigation of the packing in the cocrystal also reveals a stabilizing array of hydrogen bonds between the components of adjacent stacks. Cocrystallization with 1,5-[2-(2-hydroxyethoxy)ethoxy]naphthalene, a derivative bearing hydroxy terminated ethyleneoxy chains, gives rise to an altered structural arrangement. Alternating donor- acceptor stacks once again dominate the structure but adopt a geometry where the long axes of the constituents are essentially perpendicular. Hydrogen-bonding interactions result in the formation of continuous non-covalently linked columns of donor and acceptor subunits by linking the terminal hydroxy functions of the naphthalene component to the imide protons. The structural preferences revealed by these solid-state analyses indicate that these complexes are useful prototypes of more complex neutral supramolecular assemblies.


Author(s):  
Romana Pajkert ◽  
Henryk Koroniak ◽  
Pawel Kafarski ◽  
Gerd Volker Roeschenthaler

A one-pot, regioselective 1,3-dipolar cycloaddition of in situ generated (diethoxyphosphoryl)difluoromethyl nitrile oxide toward selected alkenes and alkynes is reported. This protocol enables facile access to 3,5-disubstituted isoxazolines and isoxazoles bearing...


2007 ◽  
Vol 40 (2) ◽  
pp. 191-198 ◽  
Author(s):  
Hakan Durmaz ◽  
Aydan Dag ◽  
Ozcan Altintas ◽  
Tuba Erdogan ◽  
Gurkan Hizal ◽  
...  

2009 ◽  
Vol 64 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Markus Woski ◽  
Norbert W. Mitzel

The reaction of (F3C)Cl2SiCl3 with the lithiated hydrazine LiN(Me)NMe2 gives the compound (F3C)Cl2SiN(Me)NMe2 (1) and in traces Cl3SiN(Me)NMe2 (2). The reactions with LiN(SiMe3)NMe2 and LiONMe2 give (F3C)Cl2SiN(SiMe3)NMe2 (4) and (F3C)Cl2SiONMe2 (5), respectively. The compounds were characterised by multinuclear solution NMR, gas-phase IR spectroscopy and mass spectrometry. Information about conformational preferences of 1 and 4 can be extracted by comparing experimental IR spectra with those calculated by quantum chemical methods (B3LYP/6-311G**). The former show the gas phase of the β -donor-acceptor silanes 1 and 4 to be dominated by the anti conformations, while the calculations show a preference for the gauche conformers. The crystal structure of Cl3SiN(Me)NMe2 (2) has been determined. The solid-state structures of the Ruppert reagent F3C-SiMe3 (1) and its chlorine analogue F3C-SiCl3 (2) have also been determined by X-ray diffraction of single crystals grown by in situ techniques.


2019 ◽  
Author(s):  
Evan Darzi ◽  
Joyann Barber ◽  
Neil Garg

We report a modular synthetic strategy for accessing heteroatom-containing polycyclic aromatic hydrocarbons (PAHs) that relies on the controlled generation of transient heterocyclic alkynes and arynes. The strained intermediates undergo in situ trapping with readily accessible oxadiazinones. Four sequential pericyclic reactions occur, namely two Diels–Alder / retro-Diels–Alder sequences, which can be performed in a stepwise or one-pot fashion to assemble four new carbon–carbon (C–C) bonds.


Author(s):  
Faiz Ahmed Khan ◽  
Karuppasamy Parasuraman

Bis-adducts of 1,2,3,4-tetrahalo-5,5-dimethoxycyclopentadiene and 1,3-butadiene, generated in situ from 3-sulfolene, have been synthesized in excellent yield. Ruthenium catalyzed oxidation of the bis-adducts followed by a one-pot transformation of the resulting α-diketone furnished oxa-bridged compounds. Unambiguous stereochemical assignments of both diastereomeric series are reported.


2015 ◽  
Vol 87 (2) ◽  
pp. 195-204 ◽  
Author(s):  
K. Yuvaraj ◽  
Dipak Kumar Roy ◽  
C. Arivazhagan ◽  
Bijnaneswar Mondal ◽  
Sundargopal Ghosh

AbstractThermolysis of an in situ generated intermediate [(Cp*Ta)2(BH3)2Cl2], 1 generated from the reaction of [Cp*TaCl4], (Cp* = η5-C5Me5) and [LiBH4·thf], in presence of [Ru3(CO)12] yielded pileo-[Cp*TaCl(μ-Cl)-B2H4Ru3(CO)8], 2 having two electrons fewer than seven pairs required for the observed square pyramidal geometry. Cluster 2 is the first example of an unsaturated cluster comprising early and late transition metals in a square pyramid core. This reaction also yielded [(Cp*Ta)2(B2H6)(B2H4Cl2)], 3 as a by-product. In addition, the reaction of [Cp*MoCl4] (Cp* = η5-C5Me5) with [LiBH4.thf] in presence of excess [MeI] at mild condition led to the isolation of periodinated dimolybdatetraborane [(Cp*Mo)2B4H3I5], 4 that hints a possible existence of [(Cp*Mo)2B4H8]. After the isolation of periodinated 4, we extended this chemistry towards the late transition metallaborane [(Cp*Rh)3B4H4], 5 using [PtBr2] as brominating source. Although all the attempts to isolate perbrominated rhodaborane failed, we have isolated partially brominated rhodaborane clusters [(Cp*Rh)3(BH)-(BBr)3], 6 and [(Cp*Rh)3(BH)3(BBr)], 7. All the compounds were characterized by IR and 1H, 11B and 13C NMR spectroscopy in solution, and the solid-state structures of 2, 4 and 6 were established by crystallographic analysis.


Sign in / Sign up

Export Citation Format

Share Document