炔烃与酸的加成

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炔烃的性质与烯烃类似可以发生亲电加成反应,但炔烃的反应性比烯烃要小一些,很多反应都可以停留在烯烃阶段。

炔烃与酸的加成

炔烃的酸催化加成遵循马氏规则,如以下的HBr加成


Tetra-n-butylammoniumbromide (16.12 g, 50 mmol) was put into a 50 ml volumetric flask and driedovernight in a vacuum desiccator. The salt was dissolved in approximately 25 mL of methylene chloride followed by trifluoroacetic acid (10 g, 6.7 ml, 89 mmol).The appropriate alkyne (10 mmol) was added. The reaction mixture was protected from light and allowed to react at room temperature for 5 to 7 days (monitored by chromatography). The entire reaction mixture was transferred to a separating funnel, washed with 2 × 100 ml water, 1 × 100 ml saturated NaHCO3, 1× 100 ml water, then dried over K2CO3 and concentrated togive a colorless oil. The solution was diluted with 50 ml of pentane and washed with 2 × 50 ml water and 1 × 20 ml brine then dried over K2CO3,filtered and concentrated under reduced pressure. At this point, the products were sufficiently pure for GC and NMR analyses.

Reference: J. Chem. Soc., PerkinTrans. 2,1523 (1998).

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