scholarly journals The Origin of Diastereofacial Control in Allylboration Reactions Using Tartrate Ester Derived Allylboronates:  Attractive Interactions between the Lewis Acids Coordinated Aldehyde Carbonyl Group and an Ester Carbonyl Oxygen [J. Am. Chem. Soc.2002,124, 10692−10697]. 

2003 ◽  
Vol 125 (12) ◽  
pp. 3668-3668 ◽  
Author(s):  
Benjamin W. Gung ◽  
Xiaowen Xue ◽  
William R. Roush
Keyword(s):  
Carbonyl Group ◽  
Lewis Acids ◽  
Carbonyl Oxygen ◽  
Ester Carbonyl

Article

1998 ◽  
Vol 76 (4) ◽  
pp. 490-497
Author(s):  
Okba Saied ◽  
Benoit Bachand ◽  
James D Wuest
Keyword(s):  
Carbonyl Group ◽  
Carbonyl Compounds ◽  
Lewis Acids ◽  
Carbonyl Oxygen ◽  
The Other ◽  
Keto Group ◽  
Carbonyl Groups ◽  
Lone Pairs ◽  
Related Compounds ◽  
Oxygen Atoms

Carbonyl oxygen atoms have two formal lone pairs of electrons. In principle, both can be used simultaneously to form complexes with two or more Lewis acids. This multiple coordination promises to have a variety of interesting consequences; unfortunately, however, complexes of carbonyl compounds with multiple Lewis acids are extremely rare. To promote multiple coordination, we have made a series of symmetric ketodiesters and related compounds in which the carbonyl group of a ketone is flanked by two additional sites of Lewis basicity. In such compounds, the flanking bases and both lone pairs of the central ketone are available for binding two equivalents of suitable Lewis acids, thereby producing symmetric double chelates in which the central ketone interacts with two Lewis acids at the same time. As expected, treatment of 3-oxoglutarates and 4-oxopimelates with TiCl4 in a 1:1 ratio yielded unsymmetric single chelates in which the carbonyl groups of the ketone and one ester bind TiCl4, while the other ester remains free. Unfortunately, treatment of the same ketodiesters with TiCl4 in a 1:2 ratio did not produce the desired symmetric double chelates. Instead, 2:4 complexes were formed in which the free esters of the unsymmetric single chelates bind TiCl4 in the normal way, without assistance from the keto group. We attribute this observation to the inherent reluctance of ketones to bind multiple Lewis acids, as well as to unfavorable Cl · · ·Cl interactions created in the hypothetical double chelates by the simultaneous attachment of two octahedrally coordinated atoms of titanium to a single carbonyl oxygen atom.Key words: Lewis acids, chelation, ketodiesters, TiCl4.

cis-2,3-Di-tert-butylcyclopropanones

1997 ◽  
Vol 75 (7) ◽  
pp. 1030-1040 ◽  
Author(s):  
T.S. Sorensen ◽  
F. Sun
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Carbonyl Group ◽  
Trans Isomer ◽  
Carbonyl Oxygen ◽  
Highly Strained ◽  
Strained Alkenes ◽  
Acyclic Compound

The preparation of the strained cis-2,3-di-tert-butylcyclopropanone 2 from the acyclic compound, α,α′-dibromodineopentyl ketone 1, using a previously reported methodology, is dramatic evidence of both the existence of oxyallyl intermediates in the mechanism of this reaction, and of the integrity with which oxyallyls ring-close to cyclopropanones by a disrotatory route. Because of the bulky cis substituents, cyclopropanone 2 exhibits a number of unusual spectroscopic features (as compared to the trans isomer 5). With the aid of ab initio calculations on 2 and 5, it can be shown that the C2—C3 bond in 2 interacts with the carbonyl π-orbitals, thus causing the carbonyl oxygen to bend 12° out of the plane; this interaction is absent in 5 and the latter has a planar carbonyl group. As with other cyclopropanones, 2 can be photochemically decarbonylated. This process itself appears to be stereospecific even though highly strained alkenes are produced. Cyclopropanone 2 is thermally rearranged to the trans isomer 5 and the kinetics for this are reported; our favoured mechanism involves oxyallyl intermediates. Other reactions of 2 also appear to proceed through these oxyallyl species; for example, alcohols initially add to 2 to give α-alkoxy ends, solutions of 2 enter into very facile diene cycloadditions, and the dimerization of neat 2 also appears to involve these oxyallyl species. Keywords: cyclopropanones, oxyallyl, stereomutation, stereospecific decarbonylation, nonplanar carbonyl.

ChemInform Abstract: Strong Lewis Acids of Air-Stable Metallocene Bis(perfluorooctanesulfonate)s as High-Efficiency Catalysts for Carbonyl-Group Transformation Reactions.

ChemInform ◽  
2012 ◽  
Vol 43 (41) ◽  
pp. no-no
Author(s):  
Renhua Qiu ◽  
Xinhua Xu ◽  
Lifeng Peng ◽  
Yalei Zhao ◽  
Ningbo Li ◽  
...  
Keyword(s):  
Carbonyl Group ◽  
Lewis Acids ◽  
High Efficiency ◽  
Group Transformation

INFRARED SPECTRA OF 2,6-DIMETHYL-4-PYRONE COMPLEXES

1961 ◽  
Vol 39 (6) ◽  
pp. 1184-1189 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Complex Formation ◽  
Oxygen Atom ◽  
Carbonyl Group ◽  
Lewis Acid ◽  
Frequency Band ◽  
Infrared Spectra ◽  
Donor Site ◽  
Carbonyl Oxygen ◽  
Acid Strength ◽  
Group A

The infrared spectra of 2,6-dimethyl-4-pyrone in solution, and in complexes with HgCl2, ZnCl2, BF3, SbCl5, and HBr have been recorded. A band at 1639 cm−1 in the free pyrone moves to progressively lower frequencies in the complexes as the Lewis acid strength increases, identifying this band as the carbonyl stretching frequency and the donor site as the carbonyl group. A higher-frequency band, at 1678 cm−1 in the free pyrone, moves to lower frequency on complex formation, but to a much smaller extent, and is to be identified with a stretching mode of the ring. The site of protonation in 2,6-dimethyl-4-pyrone salts has been unequivocally shown to be the carbonyl oxygen atom.

Oxiranes from methylenation of the ester carbonyl group by diazomethane

1988 ◽  
Vol 53 (14) ◽  
pp. 3321-3325 ◽  
Author(s):  
Paolo Strazzolini ◽  
Giancarlo Verardo ◽  
Angelo G. Giumanini
Keyword(s):  
Carbonyl Group ◽  
Ester Carbonyl ◽  
Ester Carbonyl Group

Strong Lewis Acids of Air-Stable Metallocene Bis(perfluorooctanesulfonate)s as High-Efficiency Catalysts for Carbonyl-Group Transformation Reactions

2012 ◽  
Vol 18 (20) ◽  
pp. 6172-6182 ◽  
Author(s):  
Renhua Qiu ◽  
Xinhua Xu ◽  
Lifeng Peng ◽  
Yalei Zhao ◽  
Ningbo Li ◽  
...  
Keyword(s):  
Carbonyl Group ◽  
Lewis Acids ◽  
High Efficiency ◽  
Group Transformation
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