135682-95-0

Upstream product

• 2513-25-9 2,2-dimethyl-2H-chromene 
• 180303-21-3 (1S,4R)-4,7,7-Trimethyl-3-oxo-2-oxa-bicyclo[2.2.1]heptane-1-carboxylic acid (3S,4R)-3-bromo-2,2-dimethyl-chroman-4-yl ester 
• 180469-88-9 (1S,4R)-4,7,7-Trimethyl-3-oxo-2-oxa-bicyclo[2.2.1]heptane-1-carboxylic acid (3R,4S)-3-bromo-2,2-dimethyl-chroman-4-yl ester 
• 33143-29-2 6-cyano-2,2-dimethylchromene 
• 3975-15-3 (+/-)-(3S,4R)-3-bromo-2,2-dimethyl-3,4-dihydro-2H-chromen-4-ol 
• 71649-83-7 3,4-dihydro-4-hydroxy-2,2-dimethyl-2H-benzo[b]pyran 
• 3780-33-4 2,3-dihydro-2,2-dimethylbenzo[b]pyran-4-one 
• 17235-15-3 (E)-2-(3-hydroxy-3-methylbut-1-en-1-yl)phenol 

Relevant academic research and scientific papers

Bis(catechol)salen]MnIII coordination polymers as support-free heterogeneous asymmetric catalysts for epoxidation

The formation of coordination polymers by the reaction of [bis(catechol)salen]MnIII with several di- and trivalent metal ions is reported. These polymers are insoluble in a wide range of organic solvents and water but can be dissolved upon addition of excess pyrocatechol. They function as enantioselective heterogeneous epoxidation catalysts and exhibit catalytic activity comparable to that of the homogeneous [bis(catechol)salen] MnIII building block alone when used for the enantioselective epoxidation of 2,2-dimethyl-2H-chromene. After catalysis, catalyst isolation from the reaction mixture can be readily achieved by centrifugation and decantation. Under practical oxidant concentrations, the cata lyst can be recycled up to ten times with little loss of activity and no loss of enantioselectivity. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

A metal-organic framework material that functions as an enantioselective catalyst for olefin epoxidation

A new microporous metal-organic framework compound featuring chiral (salen)Mn struts is highly effective as an asymmetric catalyst for olefin epoxidation, yielding enantiomeric excesses that rival those of the free molecular analogue. Framework confinement of the manganese salen entity enhances catalyst stability, imparts substrate size selectivity, and permits catalyst separation and reuse. The Royal Society of Chemistry 2006.

Asymmetric epoxidation of unfunctionalized alkenes with periodates catalyzed by chiral (Salen)Mn(III) complexes

Sodium and tetra-n-butylammonium periodates were used as oxidants in the asymmetric epoxidation of unfunctionalized alkenes with chiral (salen)Mn(III) complexes 1-2 together with imidazole as donor ligand. Reaction system used consisted of the alkene, oxi

Enantioselective epoxidation of non-functionalised alkenes using a urea-hydrogen peroxide oxidant and a dimeric homochiral Mn(III)-Schiff base complex catalyst

The catalytic enantioselective epoxidation of chromenes, indene and styrene using a urea-hydrogen peroxide adduct as an oxidising agent and the novel dimeric homochiral Mn(III)-Schiff base catalyst 1 has been investigated in the presence of carboxylate salts and nitrogen and oxygen coordinating co-catalysts. Conversions of more than 99% were obtained with all alkenes except styrene. Absolute chiral induction, as determined by 1H NMR using the chiral shift reagent (+)-Eu(hfc)3, was obtained in the case of nitro- and cyanochromene. The catalyst could be re-used for up to five cycles with some loss of activity due to degradation of the catalyst under epoxidation condition with retention of e.e.'s.

Encapsulation of a chiral MnIII(salen) complex in ordered mesoporous silicas: An approach towards heterogenizing asymmetric epoxidation catalysts for non-functionalized alkenes

Two immobilized chiral MnIII(salen) complexes covalently anchored on modified MCM-41 (50 A) and SBA-15 (75 A) were prepared using 3-aminopropyltriethoxysilane as a reactive surface modifier to afford comparable or even higher enantioselectivity

N-Alkyl Imidazoles as Effective Axial Ligands in the Aerobic Asymmetric Epoxidation of Unfunctionalized Olefins Catalyzed by Optically Active Manganese(III)-salen-type Complex

N-Alkyl imidazoles are effective axial ligands to achieve highly enantioselective epoxidation of unfunctionalized olefins by combined use of molecular oxygen and pivalaldehyde with optically active Mn(III)-salen-type complex catalysts.In the presence of N-alkyl imidazole, the epoxidation od 2,2-dimethylchromene proceeded smoothly to afford the corresponding optically active epoxide in 92percent enantiomeric excess.

Reverse asymmetric catalytic epoxidation of unfunctionalized alkenes

New salen Mn(III) complexes (S,S)-6a-e prepared from tartaric-derived alicyclic C2 symmetric vicinal diamines were studied in the catalysis of the asymmetric epoxidation of unfunctionalized alkenes. Although the enantioselectivities obtained we

Enantioselective epoxidation of chromenes using chiral Mn(III) salen catalysts with built-in phase-transfer capability

New chiral Mn(III) salen epoxidation catalysts 1 and 2 (a catalyst loading in the range of 2.0-0.4 mol%) have been investigated for enantioselective epoxidation of chromene derivatives to chromene epoxides using pyridine N-oxide as a proximal ligand with excellent conversions and chiral induction.

Enantiomerically pure epoxychromans via asymmetric catalysis

A practical and highly effective process for the asymmetric epoxidation of several 2,2-dimethylchromene derivatives is reported. Catalysis by Mn(salen) complex 4 in all cases affords epoxychromans with >90% ee, and this method has been applied to the synthesis of two recently developed antihypertensive agents in enantiomerically pure form.

Titanium-catalyzed asymmetric epoxidation of olefins with aqueous hydrogen peroxide: Remarkable effect of phosphate buffer on epoxide yield

The practicality of Ti(salan)-catalyzed asymmetric epoxidation was significantly improved by the addition of phosphate buffer (pH 7.4-8.0). Various olefins were transformed on a multigram scale into the corresponding epoxides with nearly complete product