Stereochemical study of the mechanism of the conversion of phenyl(trichloromethyl)carbinol to .alpha.-methoxyphenylacetic acid

Reeve, Wilkins; Bianchi, Robert J.; McKee, James R.

doi:10.1021/jo00891a016

Cited by 12 publications

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“…Racemization occurs about eight times faster than the substitution of the chlorine by hydroxyl. Racemization involves the formation of an enolate anion whereas substitution proceeds unimolecularly via an a-lactone (3,8). The relatively easy racemization of the a-chloroacetate anion makes it difficult to tell how much racemization occurs during the intramolecular migration of the chlorine.…”

Section: Stereochemistrymentioning

confidence: 99%

“…Accordingly, the observed results are consistent with complete racemization during the intramolecular chlorine migration to form chloro acetate, with the observed 9% of inverted chloro acid arising from the 17% of product not formed by the intramolecular pathway. It has previously been shown that the optical activity of the starting phenyl(trichloromethyl)carbinol is unchanged by treatment with methanolic potassium hydroxide at 40°C for 90 min (3).…”

Section: Stereochemistrymentioning

confidence: 99%

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Studies on the rearrangement of (trichloromethyl)carbinols to α-chloroacetic acids

Reeve¹,

McKee²,

Brown³

et al. 1980

Can. J. Chem.

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Phenyl(trichloromethyl)carbinol undergoes an unimolecular, predominantly intramolecular conversion into potassium α-chlorophenylacetate on stirring with 10 % aqueous potassium hydroxide at 0 °C for several days. Besides providing an interesting example of a 1–2 chlorine shift, the reaction is of potential importance for the synthesis of α-chloro acids. The study of a variety of (trichloromethyl)carbinols shows the reaction is general for secondary (trichloromethyl)carbinols as well as trichloroethanol. The mechanism of the reaction involves the preliminary formation of an epoxide. Several mechanisms are considered for the conversion of the epoxide to the α-chloroacetate anion, but none accounts for all of the experimental facts. Tertiary carbinols break down at the epoxide stage into a ketone and carbon monoxide.

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Section: Stereochemistrymentioning

confidence: 99%

Section: Stereochemistrymentioning

confidence: 99%

Studies on the rearrangement of (trichloromethyl)carbinols to α-chloroacetic acids

Reeve¹,

McKee²,

Brown³

et al. 1980

Can. J. Chem.

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“…Phenyl(trichloromethyl)carbinol is known to react with methanolic potassium hydroxide at 50°C by pathway one to form a-methoxyphenylacetic acid in 70 to 80% yield (10); and dimethyl(trichloromethyl)carbino1 (chloretone) is known to react with sodium ethoxide in ethanol to form ethyl a-ethoxyisobutyrate in 72% yield (ll), and with …”

Section: Reaction With Methanolic Potassium Hydroxidementioning

confidence: 99%

“…Most of the various reactions summarized above can occur by either of two possible mechanisms (10). In both of the mechanisms the (trichloro-'Taken in part from the doctoral thesis of Thomas F. Steckel, University of Maryland, 1970. methy1)carbinol is first converted in situ into epoxide 2.…”

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The reactions of ethyl-, vinyl-, and ethynyl(trichloromethyl)carbinols with aqueous and methanolic potassium hydroxide, thiourea, and cyanamide

Reeve¹,

Steckel²

1980

Can. J. Chem.

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. 58,2784 (1980). The reactions of ethyl(trichloromethyl)carbinol, dimethyl(trichloromethyl)carbinol, (trichloromethyl)vinylcarbinol, ethynyl (trichloromethyl)carbinol, and 1,1,1,-trichloro-3-nonyn-2-01 have been studied with the following reagents. Methanolicpotassium hydroxide: a-methoxy acids are formed in 70 and 79% yields with the ethyl-and vinylcarbinols respectively. Double bond migration to the conjugated position was observed with the vinylcarbinol. Thiourea: substituted 2-imino-4-thiazolidinones are formed in 27 to 66% yield with the first three carbinols with double bond migration in the case of the vinylcarbinol. Cyanamide: the saturated carbinols were converted to substituted ethyl 2-imino-4-0x0-I-imidazolidinecarboximidates in 30 to 60% yield. Aqueouspotassium hydroxide: a-chloro acids were formed from the ethyl-and vinylcarbinols in 23 and 24% yields respectively, again with double bond migration in the case of the vinylcarbinol.The results are discussed in terms of the known parallel reactions with phenyl (trichloromethyl)carbinol, and provide information which illustrates the usefulness and defines the llmits of certain known synthetic reactions when applied to the alkyl, alkenyl, and alkynyl trichloromethylcarbinols.WILKINS REEVE et THOMAS F. STECKEL. Can. J. Chem. 58,2784Chem. 58, (1980. On a etudie les reactions des alcools Cthyl(trichloromethyl)carbinol, dim6thyl(trichlorom~thyI)carbinol, (trichloromethy1)vinylcarbinol, ethynyl(tnchloromethyI)carbinol et trichloro-1,1,1 nonyne-3 01-2 avec divers rkactifs. Par reaction avec une solution methanolique d'hydroxyde de potassium, on obtient les a-methoxy acides avec des rendements respectifs de 70 et 79% dans le cas des alcools ethylique et vinylique. On a observe une migration de la double liaison vers la position conjuguke avec le carbinol vinylique. Avec la thiourke, il se forme des imino-2 thiazolidinones-4 substituees avec des rendements allant de 27 B 66% pour les trois premiers carbinols et une migration de la doubleliaison dans le cas du vinylcarbinol. Avec la cyanamide, les carbinols saturks se I transforment en imino-2 oxa-4 imidazolidinecarboximidates-1 substituks avec des rendements allant de 30 a 60%. Avec I'hydroxyde de potassium aqueux il y a format~on des acides a-chlorks avec des rendements respectifs de 23 et 24% dans les cas des carbinols ethylique et vinylique. On observe Ogalement une migration de la double liaison dans le cas du carbinol vinylique.On discute des rksultats en fonction des reactions paralelles connues du phenyl(trichloromethyl)carbinol. Ces rksultats fournissent des in&ormations qui illustrent I'utilitk et definissent les limites de certalnes reactions connues quand on les applique aux alkyl, alkenyl et alkynyl tr~chloromethylcarbinols [Traduit par le journal]

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Asymmetric Organocatalyzed Friedel–Crafts Reaction of Trihaloacetaldehydes and Phenols

2022

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Herein we report the asymmetric organocatalyzed method for the Friedel–Crafts reaction between activated phenols and trihaloacetaldehydes. A three‐phase screening including 41 compounds was employed to identify a catalyst structure based on 3,5‐dinitrobenzamide of 9‐amino‐epi‐cinchonidine as the lead catalytic molecule. Under the optimized reaction conditions, the above catalyst offered trihalohydroxyalkylated adducts in yields ranging from 26 to 92% and enantiomeric ratios within 69:31–99:1. The reaction scope was determined on 29 entries and several follow‐up transformations of the enantioenriched products were accomplished.

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Stereochemical study of the mechanism of the conversion of phenyl(trichloromethyl)carbinol to .alpha.-methoxyphenylacetic acid

Cited by 12 publications

References 0 publications

Studies on the rearrangement of (trichloromethyl)carbinols to α-chloroacetic acids

Studies on the rearrangement of (trichloromethyl)carbinols to α-chloroacetic acids

The reactions of ethyl-, vinyl-, and ethynyl(trichloromethyl)carbinols with aqueous and methanolic potassium hydroxide, thiourea, and cyanamide

Asymmetric Organocatalyzed Friedel–Crafts Reaction of Trihaloacetaldehydes and Phenols

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