Formation of furofurans from tetraacetylethylene. Molecular and crystal structure of a spiro[furan-2(5H),2′(3′H)-furo[2,3-b]furan]

1980 ◽  
Vol 58 (16) ◽  
pp. 1645-1650 ◽  
Author(s):  
Giorgio Adembri ◽  
Donato Donati ◽  
Renzo Cini ◽  
Rodolfo Nesi ◽  
Mirella Scotton
Keyword(s):  
Crystal Structure ◽  
Vinyl Ether ◽  
Furan Ring ◽  
Ring Closure ◽  
Molecular And Crystal Structure ◽  
Ethyl Vinyl Ether ◽  
Furan Derivative ◽  
Ethyl Vinyl ◽  
X Ray

Dimerization of tetraacetylethylene (TAE) 1 has led to a spiro[furan-2(5H),2′(3′H)-furo[2,3-b]furan], whose structure was established by X-ray analysis. The trend of TAE to furan ring closure was confirmed by the reaction with ethyl vinyl ether, where the first product of the reaction, the pyran adduct 8, smoothly rearranged to a furo[2,3-b]furan derivative 9.

A Facile Synthesis of 2,6-Dideoxy 6,6,6-Trifluorinated Carbohydrate Analogues

1998 ◽  
Vol 51 (7) ◽  
pp. 545 ◽  
Author(s):  
Colin M. Hayman ◽  
David S. Larsen ◽  
Sally Brooker
Keyword(s):  
Vinyl Ether ◽  
Boron Trifluoride Etherate ◽  
Diels Alder ◽  
Ethyl Vinyl Ether ◽  
Similar Reaction ◽  
X Ray Diffraction ◽  
Facile Synthesis ◽  
Ethyl Vinyl ◽  
X Ray ◽  
Structural Assignment

The syntheses of 2,6-dideoxy-6,6,6-trifluoro-DL-arabino-hexose (4) and the corresponding glycoside, ethyl 2,6-dideoxy-6,6,6-trifluoro-DL-arabino-hexopyranoside (11), are described. The key step in the synthesis of (4) involved the Lewis acid catalysed hetero-Diels–Alder reactions of (E)-4-benzyloxy-1,1,1-trifluorobut-3-en-2-one and benzyl vinyl ether. Hydroboration of the resulting cycloadduct, and hydrogenylitic debenzylation gave (4) in a 59% overall yield. The ethyl glycoside (11) was prepared in a similar manner from ethyl vinyl ether. A single-crystal X-ray diffraction study confirmed the structural assignment of (11). The O-glycosides (17) and (18) were formed from the boron trifluoride etherate promoted reaction of the per-acetate of (4), i.e. (16), and 2-naphthol. However, a similar reaction between 5-hydroxy-1,4-dimethoxynaphthalene and (16) gave the disubstituted C-glycoside (19) in 52% yield.

scholarly journals Diastereoselective synthesis of nitroso acetals from (S,E)-γ-aminated nitroalkenes via multicomponent [4 + 2]/[3 + 2] cycloadditions promoted by LiCl or LiClO4

2013 ◽  
Vol 9 ◽  
pp. 838-845 ◽  
Author(s):  
Leandro Lara de Carvalho ◽  
Robert Alan Burrow ◽  
Vera Lúcia Patrocinio Pereira
Keyword(s):  
Vinyl Ether ◽  
Ethyl Vinyl Ether ◽  
Diffraction Experiment ◽  
Diastereoselective Synthesis ◽  
X Ray Diffraction ◽  
Chiral Compound ◽  
Ethyl Vinyl ◽  
X Ray ◽  
Organic Solutions

Chiral nonracemic aminated nitroso acetals were synthesized via diastereoselective multicomponent [4 + 2]/[3 + 2] cycloadditions employing new (S,E)-γ-nitrogenated nitroalkenes 5a–c as heterodienes, ethyl vinyl ether (EVE) as a dienophile, and selected electron-deficient alkenes as 1,3-dipolarophiles. The employment of different organic solutions of LiClO4 or LiCl as promoter systems provided the respective nitroso acetals with yields from 34–72% and good levels of diastereoselectivity. In addition, the nitroso acetal 9c was transformed to the pyrrolizidin-3-one derivative 14c, proving the usefulness of the route in the synthesis of an interesting chiral compound. The elucidation of the stereostructures was based on 2D COSY, NOESY and HSQC NMR experiments as well as an X-ray diffraction experiment.

Cycloaddition Reactions of Arylmethylenemalonaldehydes with Olefins

1992 ◽  
Vol 57 (11) ◽  
pp. 2337-2358 ◽  
Author(s):  
Dalimil Dvořák ◽  
David Šaman ◽  
Zdeněk Arnold ◽  
Ivana Císařová ◽  
Václav Petříček
Keyword(s):  
Nmr Spectroscopy ◽  
Carboxylic Acid ◽  
Vinyl Ether ◽  
Aromatic Nucleus ◽  
Ethyl Vinyl Ether ◽  
Cycloaddition Reactions ◽  
Ethyl Vinyl ◽  
X Ray ◽  
H Nmr ◽  
Conformational Equilibria

A series of 2,4-disubstituted 3,4-dihydro-2H-pyran-5-carboxaldehydes II-XIX was prepared by reaction of substituted arylmethylenemalonaldehydes I with 2-methylpropane, 1,1-diphenylethylene, styrene, ethyl vinyl ether, 1,1-dimethoxyethylene and 1,1-bis(methylthio)ethylene. In the case of the reaction with ethyl vinyl ether the dependence of the ratio of the arising cis- and trans- 2-ethoxy-4-aryl-3,4-dihydropyran-5-carboxaldehydes VII-XIV on the substitutent on the aromatic nucleus was studied. Information on the mechanism of this reaction was obtained and conformational equilibria of 2-ethoxy-4-aryl-3,4-dihydropyran-5-carboxaldehydes in solution were studied by 1H NMR spectroscopy. The structure of trans-2-ethoxy-4-(4-chlorophenyl)-3,4-dihydropyran-5-carboxaldehyde (trans-VIII) was confirmed by X-ray analysis of the corresponding carboxylic acid trans-XXII.

scholarly journals Molekül- und Kristallstruktur von 1.1-Dimethylsilylentitanocendichlorid, (CH3)2Si(C5H4)2TiCl2 / Molecular and Crystal Structure of l,r-Dimethylsilylene Titanocene Dichloride, (CH3)2Si(C5H4)2TiCl2

1981 ◽  
Vol 36 (10) ◽  
pp. 1208-1210 ◽  
Author(s):  
Hartmut Köpf ◽  
Joachim Pickardt
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Structure Determination ◽  
Titanocene Dichloride ◽  
Molecular And Crystal Structure ◽  
Monoclinic Space Group ◽  
Crystal Data ◽  
Space Group ◽  
X Ray ◽  
Structural Dimensions

Abstract The molecular structure of the bridged [1]-titanocenophane 1,1'-dimethylsilylene titanocene dichloride, (CH3)2Si(C5H4)2TiCl2, has been investigated by an X-ray structure determination. Crystal data: monoclinic, space group C2/c, Z = 4, a = 1332.9(3), 6 = 988.7(3), c = 1068.9(3) pm, β = 113.43(2)°. The results are compared with the structural dimensions of similar compounds: 1,1'-methylene titanocene dichloride, CH2(C5H4)TiCl2, with the unbridged titanocene dichloride, (C5H5)2TiCl2 and the ethylene-bridged compound (CH2)2(C5H4)2TiCl2

Sign in / Sign up

Export Citation Format

Share Document