526208-59-3

Upstream product

• 119-36-8 methyl salicylate 
• 71367-06-1 2-hydroxy-1-deuteroformylbenzene 
• 90-02-8 salicylaldehyde 
• 69-72-7 salicylic acid 

Downstream Products

• 1108234-06-5 2-(2-(hydroxyl-dideuterium-methyl)phenoxy)-1-phenylethanone 
• 1158078-01-3 (2-(but-3-enyloxy)phenyl)methanol-d2 
• 71367-06-1 2-hydroxy-1-deuteroformylbenzene 

Relevant academic research and scientific papers

Double-chelation-assisted Rh-catalyzed intermolecular hydroacylation

(Matrix presented) Rh-Catalyzed intermolecular hydroacylation between salicylaldehydes and 1,5-hexadienes proceeded under remarkably mild reaction conditions to afford a mixture of iso- and normal-hydroacylated products in good yields. The experiments using deuterated salicylaldehyde-d revealed that "double chelation" of salicylaldehyde and 1,5-hexadiene to Rh-complex played vital roles in the catalytic cycle of intermolecular hydroacylation.

Characterization of Ground and Electronically Excited States of o-Hydroxybenzaldehyde and Its Non-Hydrogen-Bonded Photorotamer in 12 K Rare Gas Matrices.

Intramolecularly hydrogen bonded o-hydroxybenzaldehyde (OHBA-C) isolated in 12 K rare gas matrices photolyzes to a non-hydrogen-bonded rotamer (OHBA-F).IR spectra of OHBA-C, OHBA-F, and several model and isotopically substitued compounds are consistent with identification of the OHBA-F conformer as that formed by 180-deg rotation of both the hydroxy and aldehyde groups.For the two rotamers, electronic absorption, excitation, and emmission spectra are presented together with time-resolved emission measurements and estimates of a ground-state reaction enthalpy.From these data, it is proposed that the S1 state of OHBA-C is an n,?* hydrogen atom transfer-state, and S2 is a ?,?* proton-transfer state with a large ( ca. 18 kcal) barrier to reaction.Rotamerization is reversed by S1 or S2 excitation of OHBA-F.The conversion of OHBA-C to OHBA-F is ca. 5 times as efficient as the reverse process upon excitation at the respective S1 0-0 energies.An increase in photolysis quantum yield of OHBA-C is measured at energies well above the 0-0 energy and may correspond to reaction over the proposed ca. 8 kcal S1 barrier.

Rhodium-Catalyzed Annulations of 1,3-Dienes and Salicylaldehydes/2-Hydroxybenzyl Alcohols Promoted by 2-Ethylacrolein

A rhodium-catalyzed 2-ethylacrolein-promoted protocol enables the annulation reactions of 1,3-dienes with either salicylaldehydes or 2-hydroxybenzyl alcohols leading to 2-alkylchroman-4-ones with high regioselectivity. This research highlights the use of 2-ethylacrolein which probably serves as a tool of bidentate coordination to rhodium intermediates. Mechanistic studies reveal that the transformation proceeds through the 1,4-hydroacylation pathway to access unsaturated linear ketones with subsequent oxo-Michael addition. (Figure presented.).

Cobalt-Catalyzed Annulation of Salicylaldehydes and Alkynes to Form Chromones and 4-Chromanones

A unique cobalt(I)-diphosphine catalytic system has been identified for the coupling of salicylaldehyde (SA) and an internal alkyne affording a dehydrogenative annulation product (chromone) or a reductive annulation product (4-chromanone) depending on the alkyne substituents. Distinct from related rhodium(I)- and rhodium(III)-catalyzed reactions of SA and alkynes, these annulation reactions feature aldehyde C-H oxidative addition of SA and subsequent hydrometalation of the C=O bond of another SA molecule as common key steps. The reductive annulation to 4-chromanones also involves the action of Zn as a stoichiometric reductant. In addition to these mechanistic features, the CoI catalysis described herein is complementary to the RhI- and RhIII-catalyzed reactions of SA and internal alkynes, particularly in the context of chromone synthesis.

Mechanistic insights into the rhodium-catalyzed intramolecular ketone hydroacylation

[Rh((fl)-DTBM-SEGPHOS)]BF4 catalyzes the intramolecular hydroacylation of ketones to afford seven-membered lactones in large enantiomeric excess. Herein, we present a combined experimental and theoretical study to elucidate the mechanism and origin of selectivity in this C-H bond activation process. Evidence is presented for a mechanistic pathway involving three key steps: (1) rhodium(I) oxidative addition into the aldehyde C-H bond, (2) insertion of the ketone C=O double bond into the rhodium hydride, and (3) C-O bond-forming reductive elimination. Kinetic isotope effects and Hammett plot studies support that ketone insertion isthe turnover-limiting step. Detailed kinetic experiments were performed using both 1,3- bis(diphenylphosphino)propane (dppp) and (R)-DTBM-SEGPH OS as ligands. With dppp, the keto-aldehyde substrate assists in dissociating a dimeric precatalyst 8 and binds an active monomeric catalyst 9. With [Rh((R)-DTBM-SEGPHOS)]BF4, there is no induction period and both substrate and product inhibition are observed. In addition, competitive decarbonylation produces a catalytically inactive rhodium carbonyl species that accumulates over the course of the reaction. Both mechanisms were modeled with a kinetics simulation program, and the models were consistent with the experimental data. Density functional theory calculations were performed to understand more elusive details of this transformation. These simulations support that the ketone insertion step has the highest energy transition state and reveal an unexpected interactionbetween the carbonyl-oxygen lone pair and a Rh d-orbital in this transi tion state structure. Finally, a model based on the calculated transition-state geometry is proposed to rationalize the absolute sense of enantioinduction observed using (R)-DTBM-SEGPHOS as the chiral ligand.

Double-Chelation-Assisted Rh-Catalyzed Intermolecular Hydroacylation between Salicylaldehydes and 1,4-Penta- or 1,5-Hexadienes

Intermolecular hydroacylation between salicylaldehydes 1, 26-40 and 1,4-penta- or 1,5-hexadienes 4-13 by Rh-catalyst proceeded under mild reaction conditions to give a mixture of iso- and normal-hydroacylated products 14-25, 41-55, and 57-60. In the hydroacylation reaction, chelation of both salicylaldehyde and diene to the Rh-complex plays a crucial role. The ratio of iso- and normal-hydroacylated products could be regulated by the addition of salicylic acid or amines. The effects of various Rh-complexes, solvents, and additives were examined, and the plausible mechanisms of the catalytic cycle were proposed on the basis of the deuterium-labeling salicylaldehyde experiments.