Herein, we report efficient acyclic stereocontrol in tandem 1,4-addition-aldol reactions triggered by catalytic asymmetric organometallic addition. Grignard reagents add to alpha,beta-unsaturated thioesters in a 1,4-fashion and the resulting magnesium enolates are trapped with aromatic or aliphatic aldehydes. The process provides a range of tandem products bearing three contiguous stereocenters...

Complexing properties and chirality of carbohydrates were utilized in diastereoselective reactions of 0-pivaloylated N-galactosylimines with allylsilanes and -stannaries. With dyltrimethylsilane in the presence of SnCh, imines 2 of aromatic and heteroaromatic aldehydes were converted to homdylamines 3, giving ratios of diastereomers higher than 7:l. No addition products derived from a-anomeric ...

BACKGROUND Hydrophobins are small proteins produced by filamentous fungi that have a variety of biological functions including coating of spores and surface adhesion. To accomplish these functions, they rely on unique interface-binding properties. Using atomic-detail implicit solvent rigid-body Brownian dynamics simulations, we studied the diffusion of HFBI, a class II hydrophobin from Trichode...

Transfer hydrogenation of unfunctionalised and aliphatic alkenes in iPrOH/KOH is efficiently catalysed by an olefin-tethered N-heterocyclic carbene ruthenium complex, which also catalyses double bond migration as a competitive and considerably faster process.

The synthesis of new, artificial ribonucleases containing two amino acid residues connected by an aliphatic linker has been developed. Target molecules were synthesized via a catalytic three-component Ugi reaction from aliphatic diisocyanides. Preliminary investigations proved unspecific nuclease activity of the new compounds towards single-stranded RNA and double-stranded circular DNA.

We have investigated the effect of electromechanical activity on the molecular forms of acetylcholinesterase (AChE) in cultured embryonic rat myotubes. Both globular and asymmetric forms of AChE are present on the 5th day of culture when myotubes are just beginning to fibrillate. Between days 5 and 8, the 4 S (G1), 10 S (G4), and 16 S (A12) forms increase dramatically, and appreciable 12.5 S (A...

1,4-Benzoquinones have been found to prevent olefin isomerization of a number of allylic ethers and long-chain aliphatic alkenes during ruthenium-catalyzed olefin metathesis reactions. Electron-deficient benzoquinones are the most effective additives for the prevention of olefin migration. This mild, inexpensive, and effective method to block olefin isomerization increases the synthetic utility...

The responsiveness of isolated olfactory sensory neurons to stimulation with aliphatic aldehydes of varying chain length (5-10 hydrogenated carbon atoms) was investigated by means of Ca(2+ )imaging. More than half the cells examined were responsive to aliphatic aldehydes. Individual cells did not react or reacted to one or multiple aldehydes; in the latter case, cells only reacted to aldehydes ...

The multicomponent reaction between proline lithium salt, 2-cyclohexen-1-one and aliphatic aldehydes affords the 4-alkylidene-2-cyclohexen-1-ones, which are interesting fragrances, and bicyclic amino acids that bear four additional stereocenters, obtained as single stereoisomer.

Breaking the rules: Reversal of the high Markovnikov selectivity of Wacker-type oxidations was accomplished using a nitrite co-catalyst. Unbiased aliphatic alkenes can be oxidized with high yield and aldehyde selectivity, and several functional groups are tolerated. (18) O-labeling experiments indicate that the aldehydic O atom is derived from the nitrite salt.