An n→π* interaction stems from the delocalization of the electron pair (n) of a donor group into the antibonding orbital (π*) of a carbonyl group. Crystallographic analyses of five pairs of diastereoisomers demonstrate that an n→π* interaction can induce chirality in an otherwise planar, prochiral carbonyl group. Thus, a subtle delocalization of electrons can have stereochemical consequences.

Carbonyl-carbonyl (C=O···C'=O') interactions are ubiquitous in both small and large molecular systems. This interaction involves delocalization of a lone pair (n) of a donor oxygen into the antibonding orbital (π*) of an acceptor carbonyl group. Analyses of high-resolution protein structures suggest that these carbonyl-carbonyl interactions prefer to occur in pairs, that is, one donor per accep...

The formation of 1,3-diketones was observed in the reactions of bulky acyl chlorides with methyllithium. The reaction products depend on the steric hindrance around the carbonyl group of the acyl chloride and the electronic effect of the group(s) linked to the carbonyl. When the steric hindrance around the carbonyl group of the acyl chloride is big enough, the 1,3-diketone is the only product. ...

Density functional theory calculations have been employed to investigate the mechanism of gold(I)-catalysed rearrangements of cyclopropenes. Product formation is controlled by the initial ring-opening step which results in the formation of a gold-stabilised carbocation/gold carbene intermediate. With 3-phenylcyclopropene-3-methylcarboxylate, the preferred intermediate allows cyclisation via nuc...

[reaction: see text] A novel type of photo-protecting group for carbonyl compounds is described. The protecting group is readily accessed in one step from commercially available material. Installation of the protecting group upon the carbonyl compounds is achieved in excellent yields. The carbonyl compounds in their protected form are remarkably stable under various conditions and can be releas...

In enzymology, as in organic chemistry, many transformations revolve around the chemistry of the carbonyl group. A carbonyl group is electrophilic how can it be made more so? Hydrogens next to a carbonyl group have a reduced pK, how can this reactivity be promoted? Nature has found several ways to address these mechanistic challenges, the most important of which is the use of imines. Studies on...

Because carbonyl groups can participate in both hydrogen bonds and n→π* interactions, these two interactions likely affect one another. Herein, enhancement of an amidic n→π* interaction is shown to reduce the ability of β-keto amides to tautomerize to the enol, indicating decreased hydrogen-bonding capacity of the amide carbonyl group. Thus, an n→π* interaction can have a significant effect on ...

background stroke is the second cause of death and disability in the world, and oxidative stress which could be considered as a prognostic factor in patients for prevention, follow up and determination of stroke’s severity has a conceivable role in neural damage. objectives the aim of our study was to explain the association between oxidant/antioxidant imbalance as a prognostic factor in patien...