2-Phenylpropanal → 2H-Pyran, 3,6-dihydro-4,6-dimethyl-2-(1-phenylethyl)-

HRID 1057086Notes

Reaction equation

B(F)(F)F.CCOCC.[C:10]1([CH:16]([CH3:19])[CH:17]=[O:18])[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1.[CH3:20][C:21]([CH:23]=[CH:24][CH3:25])=[CH2:22]>C1(C)C=CC=CC=1>[CH3:20][C:21]1[CH2:22][CH:17]([CH:16]([C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)[CH3:19])[O:18][CH:24]([CH3:25])[CH:23]=1

Participants

Conditions

Temperature: 0 °C

Procedure

A 5-L reaction flask equipped with a reflux condenser was charged with toluene (1 L) and borontrifluride etherate (C4H10BF3O) (16 g, 0.012 mol). The reaction flask was cooled to 0° C. and 2-phenylpropanal (300 g, 2.23 mol) was added over 15 minutes. 2-Methyl-1,3-pentadiene (1.22 Kg, 4.92 mol) was added over 1 hour. During the feed, the reaction exothermed to 10° C. The reaction mixture was aged overnight and then quenched with aqueous sodium hydroxide (50%, 1 L). Vacuum distillation of the resulting mixture afforded 4,6-dimethyl-2-(1-phenyl-ethyl)-3,6-dihydro-2H-pyran (120 g) having a boiling point of 118-120° C. at 3 mmHg.

Workup

customequipped with a reflux condenser
customDuring the feed, the reaction exothermed to 10° C
customquenched with aqueous sodium hydroxide (50%, 1 L)
distillationVacuum distillation of the resulting mixture

Sources & evidence

ORD record: ord-6967f0f8f8834f6b936c235aaac0162a
Source dataset: uspto-grants-2016_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09399751B1

Reaction notes

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