Quinone → Ammonium Hydroxide

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a 0° C. solution of p-benzoquinone (1.06 g, 9.79 mmol) in THF (50 mL), was added by cannula solution of lithium phenylacetylide (9.79 mmol; generated as described in Example 23a) in THF (25 mL). After stirring at 0° C. for 15 min, a solution of the Grignard BrMg(CH2)3N(CH3)2 (12.2 mL), 1.6M in THF) and N,N-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (13.5 mL, 112 mmol) was added by cannula. The ice bath was then removed and the reaction was allowed to warm to 23° C. and stir for 1 hr. At this time, TLC (30% EtOAc/hexane) showed no remaining dienone. The reaction was quenched by addition to H2O and Et2O. An emulsion formed which was broken up by addition of saturated NH4Cl. After back extracting the aqueous phase with Et2O (3 times), the combined organic phases were dried (MgSO4) and evaporated leaving a dark brown oil. Column chromatography (flash SiO2, 20% MeOH/CHCl3 and 0.1% NH4OH) of this oil gave 1.12 g of desired title product as a brown gum which crystallized on standing (39% yield).

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