Ethynyl carbinol prepn. from unsatd. ketones - pref. methyl vinyl ketone, by ethynylation with magnesium acetylene complex in liq. ammonia

摘要

Prepn. of ethynyl carbinols of formula R1R2C=CR-C(OH)-(-C=CH)R3 (I) (where R,R1 and R3 are H, lower alkyl or lower alkenyl, R2 is H or 1-18C hydrocarbyl, or R1 and R2 together with the C atom, to which they are attached, denote cyclo-lower alkyl or cyclo-lower alkenyl) take place by reacting a cpd. R1R2C=CR-CR3O (II) pref. Me vinyl ketone in liq. NH3 with an Mg acetylene complex (III) as ethynylation reagent pref. used as a mixt. contg. >5 (5-95) esp. 10-80 wt. % (III) and Na acetylide. (I) are obtd. in high yields, e.g. 70 wt. % (compared with 30% when using Na acetylide as ethynylation reagent) and improved purity e.g. 94%. Ethynylation reagent is pref. prepd. by mixing Na acetylide with MgSO4, MgCl2, MgF2 or an organo Mg halide esp, EtMgBr, in liq. NH3, under anhydrous conditions. Pref. mixt. contains 10-95 wt. % Na acetylide w.r.t. Mg cpd. + Na acetylide. (IIIe be prepd. by reacting C2H2 with Mg in liq. NH3 in presence of Na amide or Na metal at -100 to +100 degrees C under 15-1000 psia.