Oxygen singly bonded

Arguably the most challenging aspect for the preparation of 1 was construction of the unsymmetrically substituted sec-sec chiral bis(trifluoromethyl)benzylic ether functionality with careful control of the relative and absolute stereochemistry [21], The original chemistry route to ether intermediate 18 involved an unselective etherification of chiral alcohol 10 with racemic imidate 17 and separation of a nearly 1 1 mixture of diastereomers, as shown in Scheme 7.3. Carbon-oxygen single bond forming reactions leading directly to chiral acyclic sec-sec ethers are particularly rare since known reactions are typically nonstereospecific. While notable exceptions have surfaced [22], each method provides ethers with particular substitution patterns which are not broadly applicable. 

The formation of carbon-oxygen single bonds via the attack of an alkoxide on an alkyl halide, (Williamson ether synthesis) is an extremely important reaction that... 

C—Organic bases are, in general, amines (contain N). An ether would have an oxygen single-bonded to two carbons (R groups). An aldehyde has oxygen double-bonded to a carbon at the end of a chain. Aldehydes (RCHO) and... 

However, we must recognize that the large driving force for this reaction comes from two sources (1) the formation of the carbon-oxygen single bond—Reaction 1—which is exothermic by about 28 kcal. This initially... 

Similar constancy is shown by other covalent bond distances (with certain exceptions that will be discussed later). For the carbon— oxygen single bond, for example, the value 1.43 A has been reported for methanol,4 ethanol, ethylene glycol, dimethyl ether, paraldehyde, metaldehyde, and many other molecules this value is accepted as standard for the C—O bond. 

The 1,2-migration of a silicon moiety to the oxygen anion of a carbon-oxygen single bond produced by nucleophilic addition to a carbonyl group (Brook... 

Unsymmetrical alkyl phenyl tellurium derivatives were prepared in good yields from phenyl trimethylsilyl tellurium and epoxides, carboxylic acid esters, and linear or cyclic ethers under very mild conditions. In these reactions, which proceed in dichloromethane in the presence of a catalytic amount of zinc iodide, a carbon-oxygen single bond is cleaved. The highly nucleophilic benzenetellurolate binds to the carbon fragment, whereas the trimethylsilyl group becomes linked to the oxygen. 

C) The bond lengths in the nitrate ion, N03, are all identical and shorter than a nitrogen-oxygen single bond. 

AH = -83 kj The carbon-oxygen double bond is stronger than two carbon-oxygen single bonds hence C02 and H20 are more stable than H2C03. 63. Three resonance structures can be drawn... 

Actual measurement shows that all the carbon-oxygen bonds in CaC03 have the same length, 1.31 A, as compared with a usual length of about 1.36 A for a carbon-oxygen single bond and about 1,23 A for a carbon-oxygen double bond. What is a better representation of the CO3" ion ... 

In the ketone there is a carbon/oxygen double bond, three C-H bonds from an sp carbon and one carbon/carbon single bond. In the enol tautomer, in contrast, there are two C-H bonds from an sp2 carbon, a carbon/carbon double bond, a carbon/oxygen single bond and an O-H bond. This may be simplified by assuming that a C-H bond from an sp carbon is about as stable as a C-H bond from an sp carbon. Now one is looking at the difference between one carbon/oxygen double bond plus one C C bond and plus one C-H bond for the ketone, and one carbon/carbon double bond plus one C-0 bond and plus one O-H bond for the enol tautomer. 

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