反催化的

The normally brominated Baylis-Hillman adducts were formed as the major product at low temperature. While at room temperature or heating, the α,γand β,β-dibrominated compounds were formed as the major products using 3-butyn-2-one and methyl propiolate or propynenitrile as substrate, respectively.

贫电子炔类化合物的Baylis-Hillman反应的研究在这部分工作中我们发现在用TiBr〓或BBr〓为Lewis酸催化贫电子炔类化合物和芳香醛的Baylis-Hillman反应时，温度对反应的影响很大：当反应在低温下进行时，通常生成的是正常的β-溴代的Baylis-Hillman反应产物；而在室温或加热条件下反应，以丁炔酮为底物时，主要生成的是α，γ-二溴化合物，而以丙炔酸甲酯及丙炔腈为底物时，主要生成的是β，β-二溴化合物。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。