3末端炔烃的卤化 RC=CH+HOBr RC=C-Br+H,O 4.4.2加氢与还原 R-C=C-R'+H2 pd R R' H2 C=0 RCH2CH2R H H pd Lindlar Cat.R R RC=CR'+H2 C-C (顺式烯烃 H H