19936-75-5

Upstream product

• 67-56-1 methanol 
• 74730-21-5 4S-(+)-illicinone-A 
• 59893-87-7 2-hydroxy-4,5-dimethoxyallylbenzene 
• 2880-58-2 2-methoxy-1,4-benzoquinone 
• 762-72-1 allyl-trimethyl-silane 
• 97-53-0 4-allylguaiacol 

Relevant academic research and scientific papers

Regioselective Lewis acid-directed reactions of 2-alkoxy-5-alkyl-1,4-benzoquinones with styrenes: Synthesis of burchellin and guianin neolignans

Reactions of 2-carbomethoxy-5-methoxy-1,4-benzoquinone with (E)-propenylbenzenes promoted by Ti(IV) regio- and stereoselectively yield trans 2-aryl-4-carbomethoxy-7-methoxy-3-methyl-2,3-dihydro-5-benzofuranols. However, the products found in Lewis acid-promoted reactions of 2-alkoxy-5-alkyl-1,4-benzoquinones with (E)-propenylbenzenes depend on the nature of the Lewis acid. Low-temperature reactions with SnCl4 produce rel-(1R,6S,7S,8R)-4-alkoxy-1-alkyl-7-aryl-8-methylbicyclo[4.2.0]oct-3- ene-2,5-diones 21-23 and products derived from them. Allowing the reactions to warm to room temperature results in rel-(2S,3S,3aR)-3a-alkyl-2-aryl-5-hydroxy-3-methyl-2,3,3a,6-tetrahydro -6-oxobenzofurans as mixtures of keto-enol tautomers 26/27 and 28/29. With Ti(IV) as promoter, the reactions can be made to produce either 21-23 or the regioisomeric rel-(1S,6R,7R,8S)-4-alkoxy-1-alkyl-8-aryl-7-methylbicyclo[4.2.0]oct-3- ene-2,5-diones 18-20. The ratio of the two depends upon the makeup of the Ti(IV) promoter and the substituents on the propenylbenzene. A mechanistic rationale is presented involving regioselective coordination of the different Lewis acids to the quinone. Thus, SnCl4 binds to the C-1 carbonyl and C-2 alkoxy oxygens, forming a complex possessing a 2-alkoxy-5-alkyl-4-oxo-2,5-cyclohexadienyl carbocation moiety (e.g. 30) which undergoes a thermally allowed 4π + 2π (5 + 2) cycloaddition with propenylbenzene to give a bicyclo[3.2.1]octenyl carbocation 31; this cation then rearranges to the observed products. On the other hand, the Ti(IV)-promoted reactions give either bicyclo[3.2.1]octenyl carbocation 31 or 34, depending upon reaction conditions, followed by rearrangement. Cyclobutanes 18-20 undergo protic acid rearrangement to give trans 7-alkoxy-4-alkyl-2-aryl-3-methyl-2,3-dihydro-5-benzofuranols 15-17, whereas cyclobutanes 21-23 yield 5-alkyl-7-aryl-3-hydroxy-6-methylbicyclo[3.2.1]oct-3-ene-2,8-diones 24/25. The reactions provide an efficient and stereoselective route to neolignans of the guianin and burchellin classes.

Ruthenium-catalyzed oxidative dearomatization of phenols to 4-(tert-butylperoxy)cyclohexadienones: Synthesis of 2-substituted quinones from p-substituted phenols

The ruthenium-catalyzed oxidation of phenols with tert-butylhydroperoxide efficiently gives the corresponding 4-(tert-butylperoxy)cyclohexadienones. The oxidation proceeds selectively because of ruthenium's ability for rapid single-electron transfer. This biomimetic oxidation reaction is highly useful to obtain the metabolic compounds desired for confirming the safety of medicines and related compounds. Typically, the first metabolic compound of the female hormone estrone is readily obtained by this biomimetic oxidation reaction. The resulting 4-(tert-butylperoxy)cyclohexadienones are versatile synthetic intermediates, which can be transformed into 2-substituted 1,4-benzoquinones by treatment with acid catalysts. Acid-promoted rearrangement followed by a Diels-Alder reaction provides a new strategy for the synthesis of fused cyclic compounds, such as naphthoquinone and anthraquinone derivatives, from readily available phenols. The nonnatural 1,4-diacetoxy steroidal skeleton is obtained by the oxidation of estrone followed by zinc-mediated migration. Vitamin K 3 is synthesized selectively from p-cresol in an overall 79 % yield in 4 steps, and the synthesis includes the ruthenium-catalyzed oxidation.

STEREOSELECTIVE SYNTHESES OF THREE DIFFERENT CLASSES OF NEOLIGNANS FROM THE SAME STARTING MATERIALS

Lewis Acid catalyzed reactions of 2-alkoxy-5-allyl-1,4-benzoquinones with styrenes can be manipulated to form either the burchellin or guianin neolignans, or 4-allyl-2-aryl-3-methyl-2,3-dihydrobenzofurans.

EFFICIENT SYNTHESIS OF SEVERAL ANIBA AND MAGNOLIA NEOLIGNANS

The novel neolignans isolated from the plants Aniba burchellii, A. simulans and Magnolia denudata have been efficiently synthesized by means of electrochemical method.