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All 3 posts Subject: New synthesis of phenylacetones Please login to post Down

psychokitty
(«»)
09-14-04 07:12
No 531247
      New synthesis of phenylacetones
(Rated as: good read)

This one looks like a variation of the thallium nitrate rearrangement of B-methylstyrenes to that of a-arylketones:

Lego
(Hive Bee)
09-14-04 09:09
No 531259
User Picture       Phenylacetones from alpha-methyl-styrenes
(Rated as: excellent)

Oxidative rearrangements of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol: a general, regiospecific synthesis of alpha-aryl ketones
Michael W. Justik and Gerald F. Koser
Tet. Lett., 2004, 45(32), 6159-6163
DOI:10.1016/j.tetlet.2004.06.029
Fulltext: Post 531247 (psychokitty: "New synthesis of phenylacetones", Novel Discourse)

Abstract: The treatment of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol affords the corresponding alpha-aryl ketones. This oxidative rearrangement is general for acyclic and cyclic arylalkenes and permits regioselective syntheses of isomeric alpha-phenyl ketone pairs.

Synthesis of [hydroxy(tosyloxy)iodo]benzene:

Hypervalent Organoiodine. Reactions of Silver Arylsulfonates with Iodosobenzene Dichloride
Gerald F. Koser, Richard H. Wettach
J. Org. Chem., 1977, 42, 1476-1478

Iodosobenzene diacetate (1)

Reaction of 1 with p-Toluenesulfonic Acid in CH₃CN. p-Toluenesulfonic acid monohydrate (7.61 g, 40 mmol), dissolved in a minimum quantity of CH₃CN, was added to a solution/suspension of 1 (6.44 g, 20 mmol) in CH₃CN (45 mL) at room temperature. The reaction mixture immediately cleared and turned yellow and, upon standing at room temperature, gave phenylhydroxyltosyloxyiodine (4a) as fine white needles with a yellowish hue. Two crops were isolated, yield 7.62 g (93%). The crude product was washed with acetone (removes p-toluenesulfonic acid) and ether (removes acetic acid) and dried: mp 135-138 °C

Synthesis of iodosobenzene diacetate

Easy Preparation of (Diacetoxyiodo)arenes from Iodoarenes with Sodium Percarbonate as the Oxidant
Agnieszka Zielinska and Lech Skulski
Molecules, 2002, 7(11), 806-809.pdf (http://www.mdpi.org/molecules/papers/71100806.pdf)

Sodium percarbonate (18.4 mmol, 330% excess) was slowly added portionwise to a stirred mixture of Ac₂O (7.0 mL), AcOH (5.8 mL), and CH₂Cl₂ (40 mL). The stirring was continued for 1.5 h at <= 30°C. An appropriate iodoarene was then added (6.4 mmol), and the reaction mixture was then stirred at 40°C for 5 h. After cooling, the precipitated CH₃COONa was collected by filtration under reduced pressure, washed with CH₂Cl₂ (2 x 15 mL) and discarded. The filtrates were evaporated under vacuum, and cold (0-5 °C) 10% aq. CH₃COOH (15 mL) was rapidly added. The flask was left in a cooler for a few hours. The colorless crystals formed were collected by filtration, washed with hexane and air-dried in the dark. Most of those crude products thus obtained need not be further purified, as they were 96-99% pure, according to iodometric analysis [6]. When necessary, the crude products were recrystallized from AcOEt/Ac₂O (9:1, v/v) [2]. They should be stored in the dark, preferably in a cooler. See Table 1 for more details. Under these conditions 4-iodotoluene and 4-chloroiodobenzene were unexpectedly oxidized to the corresponding iodylarenes (recrystallized from boiling water).

[2] Kazmierczak, P.; Skulski, L. A Simple, Two-Step Conversion of Various Iodoarenes to (Diacetoxyiodo)arenes with Chromium(VI) Oxide as the Oxidant. Synthesis 1998, 1721-1723, and references therein.
[6] Lucas, H. J.; Kennedy, E. R.; Formo, M. W. Org. Synth. 1942, 22, 70.

For a synthesis without acetic anhydride but with peracetic acid/acetic acid, see:
Organic Syntheses, CV 5, 660 (http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0660)

The tendency is to push it as far as you can

Rhodium
(Chief Bee)
09-14-04 14:14
No 531279
User Picture       alpha-Methylstyrenes to P2P

Interesting - this is very similar to the patent I discovered the other day: Post 530316 (Rhodium: "Novel route to P2P from alpha-methylstyrene", Novel Discourse)

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	All 3 posts		Subject: New synthesis of phenylacetones		Please login to post		Down


		psychokitty («») 09-14-04 07:12 No 531247				New synthesis of phenylacetones (Rated as: good read)
						This one looks like a variation of the thallium nitrate rearrangement of B-methylstyrenes to that of a-arylketones:



		Lego (Hive Bee) 09-14-04 09:09 No 531259				Phenylacetones from alpha-methyl-styrenes (Rated as: excellent)
						*Oxidative rearrangements of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol: a general, regiospecific synthesis of alpha-aryl ketones* Michael W. Justik and Gerald F. Koser Tet. Lett., 2004, 45(32), 6159-6163 DOI:10.1016/j.tetlet.2004.06.029 Fulltext: Post 531247 (psychokitty: "New synthesis of phenylacetones", Novel Discourse) Abstract: The treatment of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol affords the corresponding alpha-aryl ketones. This oxidative rearrangement is general for acyclic and cyclic arylalkenes and permits regioselective syntheses of isomeric alpha-phenyl ketone pairs. Synthesis of [hydroxy(tosyloxy)iodo]benzene: Hypervalent Organoiodine. Reactions of Silver Arylsulfonates with Iodosobenzene Dichloride Gerald F. Koser, Richard H. Wettach J. Org. Chem., 1977, 42, 1476-1478 Iodosobenzene diacetate (1) Reaction of 1 with p-Toluenesulfonic Acid in CH₃CN. p-Toluenesulfonic acid monohydrate (7.61 g, 40 mmol), dissolved in a minimum quantity of CH₃CN, was added to a solution/suspension of 1 (6.44 g, 20 mmol) in CH₃CN (45 mL) at room temperature. The reaction mixture immediately cleared and turned yellow and, upon standing at room temperature, gave phenylhydroxyltosyloxyiodine (4a) as fine white needles with a yellowish hue. Two crops were isolated, yield 7.62 g (93%). The crude product was washed with acetone (removes p-toluenesulfonic acid) and ether (removes acetic acid) and dried: mp 135-138 °C Synthesis of iodosobenzene diacetate Easy Preparation of (Diacetoxyiodo)arenes from Iodoarenes with Sodium Percarbonate as the Oxidant Agnieszka Zielinska and Lech Skulski Molecules, 2002, 7(11), 806-809.pdf (http://www.mdpi.org/molecules/papers/71100806.pdf) Sodium percarbonate (18.4 mmol, 330% excess) was slowly added portionwise to a stirred mixture of Ac₂O (7.0 mL), AcOH (5.8 mL), and CH₂Cl₂ (40 mL). The stirring was continued for 1.5 h at <= 30°C. An appropriate iodoarene was then added (6.4 mmol), and the reaction mixture was then stirred at 40°C for 5 h. After cooling, the precipitated CH₃COONa was collected by filtration under reduced pressure, washed with CH₂Cl₂ (2 x 15 mL) and discarded. The filtrates were evaporated under vacuum, and cold (0-5 °C) 10% aq. CH₃COOH (15 mL) was rapidly added. The flask was left in a cooler for a few hours. The colorless crystals formed were collected by filtration, washed with hexane and air-dried in the dark. Most of those crude products thus obtained need not be further purified, as they were 96-99% pure, according to iodometric analysis [6]. When necessary, the crude products were recrystallized from AcOEt/Ac₂O (9:1, v/v) [2]. They should be stored in the dark, preferably in a cooler. See Table 1 for more details. Under these conditions 4-iodotoluene and 4-chloroiodobenzene were unexpectedly oxidized to the corresponding iodylarenes (recrystallized from boiling water). [2] Kazmierczak, P.; Skulski, L. A Simple, Two-Step Conversion of Various Iodoarenes to (Diacetoxyiodo)arenes with Chromium(VI) Oxide as the Oxidant. Synthesis 1998, 1721-1723, and references therein. [6] Lucas, H. J.; Kennedy, E. R.; Formo, M. W. Org. Synth. 1942, 22, 70. For a synthesis without acetic anhydride but with peracetic acid/acetic acid, see: Organic Syntheses, CV 5, 660 (http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0660) The tendency is to push it as far as you can



		Rhodium (Chief Bee) 09-14-04 14:14 No 531279				alpha-Methylstyrenes to P2P
						Interesting - this is very similar to the patent I discovered the other day: Post 530316 (Rhodium: "Novel route to P2P from alpha-methylstyrene", Novel Discourse) ^{The Hive - Clandestine Chemists Without Borders}

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