Sigmatropic rearrangements number among the most powerful complexity-building transformations in organic synthesis but have remained largely insensitive to enantioselective catalysis due to the diffuse nature of their transition structures. Here, we describe a synergistic ion-binding strategy for asymmetric catalysis of anionic sigmatropic rearrangements. This approach is demonstrated with the ...

The approach using pyrrolidine enamine as substrate has been studied for this synthesis, and an important catalyst structural feature has been developed. After survey of pyrrolidine-based Brønsted acid catalyst, tetrazole catalyst (3f) was found to be optimal in synthesis of aminooxy carbonyl compounds in high yields, with complete enantioselectivity not only for aldehydes but also for ketones.

ome of the most useful reactions of carbonyl compounds involve carbonhydrogen bonds adjacent to the carbonyl group. Such reactions, which can be regarded as the backbone of much synthetic organic chemistry, usually result in the replacement of the hydrogen by some other atom or group, as in the I I I I sequence H-C-C=O -+ X-C-C=O. The important examples we I I will consider in this chapter are ...

The direct α-vinylation of carbonyl compounds to form a quaternary stereocenter is a challenging transformation. It was discovered that δ-oxocarboxylic acids can serve as masked vinyl compounds and be unveiled by palladium-catalyzed decarbonylative dehydration. The carboxylic acids are readily available through enantioselective acrylate addition or asymmetric allylic alkylation. A variety of α-...

An easy to operate method of catalytic hydroboration of unsaturated compounds has been developed with wide substrate scope. Reactions of various aldimines, ketimines, α,β-unsaturated carbonyl compounds, and alkynes were successfully executed with bis(pinacolato)diboron and N-heterocyclic carbenes in methanol without requiring a transition metal or inert atmosphere.

A synthetic equivalent of the Nazarov reagent, the silyl derivative 2, able to undergo base-catalyzed double Michael addition reactions with α,β-unsaturated carbonyl compounds has been developed. The new reagent satisfactorily reacts with unsaturated indolo[2,3-a]quinolizidine lactams to give pentacyclic yohimbinone-type derivatives.

Aromatic carbonyl compounds such as 10-methylacridone form the Lewis acid complexes including paramagnetic and redox active Lewis acids. The fluorescence energies of the Lewis acid complexes are well correlated with the O2*--Lewis acid complexes derived from the gzz-values of the ESR spectra of the superoxide anion-Lewis acid complexes, thus providing a quantitative measure of the Lewis acidity.

The compounds 2-(1-benzo-furan-2-yl)-2-oxoethyl 2-nitro-benzoate, C17H11NO6 (I), and 2-(1-benzo-furan-2-yl)-2-oxoethyl 2-amino-benzoate, C17H13NO4 (II), were synthesized under mild conditions. Their mol-ecular structures were characterized by both spectroscopic and single-crystal X-ray diffraction analysis. The mol-ecular conformations of both title compounds are generally similar. However, dif...

The title compound, C(36)H(24)O(6)·CH(2)Cl(2), is a dimer of two essentially planar (r.m.s., deviations of fitted plane of 14 pyracene C atoms = 0.0539 and 0.0543 Å) tetra-cyclic pyracene frameworks (each with four methyl groups and three carbonyl groups on the peripheral carbon atoms) twisted along a central C=C bond with an angle of 50.78 (3)° at 90 K. There are notably long Csp(2)-Csp(2) bon...

Previous preparation of iron phosphide nanowires usually employed toxic and unstable iron carbonyl compounds as precursor. In this study, we demonstrate that iron phosphide nanowires can be synthesized via a facile nonaqueous chemical route that utilizes a commonly available iron precursor, iron (III) acetylacetonate. In the synthesis, trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO) ...