Dehydrogenation Of Primary Alcohols Research Articles

Enantioselective iridium-catalyzed vinylogous Reformatsky-aldol reaction from the alcohol oxidation level: linear regioselectivity by way of carbon-bound enolates.

Enantioselective iridium-catalyzed vinylogous Reformatsky-aldol reaction from the alcohol oxidation level: linear regioselectivity by way of carbon-bound enolates.

PNP pincer osmium polyhydrides for catalytic dehydrogenation of primary alcohols

This paper reports the synthesis, structure, and properties of a series of PNP pincer complexes of osmium OsH(3)Cl[HN(C(2)H(4)P(i)Pr(2))(2)] (1), OsH(3)[N(C(2)H(4)P(i)Pr(2))(2)] (2), OsH(4)[HN(C(2)H(4)P(i)Pr(2))(2)] (3), and OsH(2)(PMe(3))[HN(C(2)H(4)P(i)Pr(2))(2)] (4). The tetrahydride 3 operates as an efficient catalyst at 0.1 mol% loading for the reactions of amination and dehydrogenative coupling of primary alcohols, producing secondary amines and symmetrical esters, respectively. The catalyst 3 is distinguished by outstanding stability, and it can be used in an aqueous environment at temperatures as high as 200 °C.

ポリケタイドの全合成研究における新展開―不斉補助基からの脱却―

The complex issues of stereoselectivity posed by polyketides are most often addressed through the use of chiral auxiliaries, chiral reagents, and premetalated nucleophiles. Prof. Krische’s approach takes advantage of carbonyl allylation and crotylation protocols, wherein primary alcohol dehydrogenation concurrently triggers aldehyde formation and reductive generation of allyliridium nucleophiles, enabling asymmetric carbonyl allylation and crotylation directly from the alcohol oxidation level. His approach circumvents additional manipulations associated with the use of non-native functional groups or substructures to mediate bond construction, as evident in the use of chiral auxiliaries, and minimizes (re)functionalizations, especially redox manipulations.

Facile Conversion of Alcohols into Esters and Dihydrogen Catalyzed by New Ruthenium Complexes.

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Facile Conversion of Alcohols into Esters and Dihydrogen Catalyzed by New Ruthenium Complexes

An efficient, environmentally benign method for the preparation of esters from alcohols under mild, neutral conditions without the need for carboxylic acid derivatives and condensing agents was developed. Catalyst design, based on new Ru(II) hydrido carbonyl complexes incorporating electron-rich PNP and PNN ligands has resulted in the novel complex (I) which is an outstanding catalyst for the dehydrogenation of primary alcohols to esters and H(2) under neutral conditions.

Triruthenium Dodecacarbonyl/Triphenylphosphine Catalyzed Dehydrogenation of Primary and Secondary Alcohols.

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Triruthenium dodecacarbonyl/triphenylphosphine catalyzed dehydrogenation of primary and secondary alcohols

Dehydrogenation of alcohols into aldehydes and ketones by Ru 3(CO) 12/PPh 3 based homogeneous catalysis has been investigated as an alternative for the classical Oppenauer oxidation. Several catalytic systems have been screened in the Oppenauer-like oxidation of alcohols. A systematic study of various combinations of Ru 3(CO) 12, mono- and bidentate ligands and hydride acceptors was performed to enable dehydrogenation of primary alcohols to stop at the aldehyde stage. Among many H-acceptors screened, diphenylacetylene (tolane) proved the most suitable judged from its smooth reduction. Electron rich and deficient analogues of tolane have been synthesized and, based on competition experiments between these H-acceptors, a tentative catalytic cycle for the Ru 3(CO) 12/PPh 3-catalyzed dehydrogenations has been proposed.

Highly Sustainable Catalytic Dehydrogenation of Alcohols with Evolution of Hydrogen Gas.

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Highly sustainable catalytic dehydrogenation of alcohols with evolution of hydrogen gas

The catalytic dehydrogenation of alcohols into aldehydes and ketones in the absence of H-acceptors was studied with several transition metal catalysts in order to develop a large-scale procedure. Applying Ru(OCOCF 3) 2(CO)(PPh 3) 2, the so called Robinson catalyst, several secondary alcohols could be dehydrogenated with high selectivity into the corresponding ketones in relatively short reaction times. Highly effective atom utilization could be realized avoiding solvents and giving hydrogen gas as the sole by-product. However, in contrast to Robinson's work the catalytic dehydrogenation of primary alcohols appeared to be problematic due to decarbonylation with concomitant catalyst deactivation and aldol condensation under the strong acid or basic conditions applied.

Catalytically reactive (η 4-tetracyclone)(CO) 2(H) 2Ru and related complexes in dehydrogenation of alcohols to esters

(η 4-Tetracyclone)(CO) 3Ru and [(η 4-tetracyclone)(CO) 2Ru] 2 are catalyst precursors in the direct oxidation of primary alcohols to esters. Their use without a H-acceptor in an open reaction system leads to bimolecular dehydrogenation of primary alcohols to esters and also of secondary alcohols to ketones with evolution of H 2. The structure of (η 4-tetracyclone)(CO) 2(H) 2Ru was assigned to a reaction intermediate observed during the catalysis. A catalytic cycle is proposed.

Kinetics of Catalytic Dehydroge nation of Primary Alcohols

Kinetics of Catalytic Dehydroge nation of Primary Alcohols