1608-72-6Relevant articles and documents
Revised Mechanisms for Aldehyde Disproportionation and the Related Reactions of the Shvo Catalyst
Gusev, Dmitry G.,Spasyuk, Denis M.
, p. 6851 - 6861 (2018/06/25)
It is widely believed that the Shvo catalyst (1) dissociates to form two active species in solution: the 18-electron hydride RuH(CO)2[η5-C5(OH)Ph4] (2) and the naked 16-electron complex Ru(CO)2[η4-C5(=O)Ph4] (3). This combined experimental/computational study demonstrates that a sustained presence of 3 is not viable in the reactions of alcohols and organic carbonyls; thus, 3 is better treated as nonexistent under the typical catalytic conditions. We propose a modified view where the key catalytic species are the hydride 2 and the 18-electron metal alkoxide intermediate Ru(OR)(CO)2[η5-C5(OH)Ph4] existing in equilibrium with the corresponding alcohol complex. An X-ray crystallographic study of 2 revealed an interesting dihydrogen-bonded dimer structure in the solid state. The mechanistic ideas of this paper explain the highly efficient Tishchenko-like aldehyde disproportionation reaction with the Shvo catalyst. Additionally, our observations explain why 1 is inefficient for hydrogenation of ethyl acetate and for the acceptorless dehydrogenative coupling of ethanol. Our findings provide practical guidance for future catalyst design on the basis of the Shvo ruthenium dimer prototype.
HEMIACETYL PROFLAVORS
-
Page/Page column 15, (2016/07/27)
Provided herein is a compound having the formula I (I), wherein R1 and R2 are independently selected from a branched or straight C1-C6 alkyl and a C1-C6 alkenyl, n is 1, 2, 3, 4, 5 or 6 and x is independently 0, 1 or 2; provided that when n is 1, x is 2. Also provided herein is a method of releasing acetaldehyde into an aqueous solution comprising delivering a compound of formula I to the aqueious solution wherein R1 and R2 are independently selected from a branched or straight C1-C6 alkyl and a C1-C6 alkenyl, n is 1, 2, 3, 4, 5 or 6 and x is independently 0, 1 or 2; provided that when n is 1, x is 2. Also provided is a flavor or aroma-modifying composition 1 comprising: i) a flavor or aroma-conferring or modifying ingredient, at least one compound according to formula (I) above; ii) at least one ingredient selected from the group consisting of a flavor carrier and a flavor base; and iii) optionally at least one flavor adjuvant.
COPPER SALTS CATALYSED ADDITION OF ALCOHOLS AND ACIDS TO ENOL ETHERS
Tordeux, M.,Dorme, R.,Wakselman, C.
, p. 629 - 634 (2007/10/02)
Enol ethers have been used for the protection of alcohols (1a) and acids (1b,2).The addition of the hydroxyl group on the double bond of the enol ether has been performed, so far, in the presence of a Broensted acid.
