A general palladium‐catalyzed method for the direct alkynylation of unactivated alkenes via C−H activation, was successfully developed, with the assistance of 8‐aminoquinoline. It is applicable to both internal and terminal unactivated alkenes with a broad functionality tolerance. This method shows good regio‐ and diastereoselectivity and provides an alternative approach for directing construct of conjugated 1,3 ‐enynes.
We reported a mid-infrared intra-cavity ZnGeP2 optical parametric oscillator (ZGP OPO) pumped by an acousto-optic (AO) Q-switched Ho:YAG oscillator. The 1908nm laser with an output power of 20W was used as the pump source of the Ho:YAG AO Q-switched oscillator. ZGP OPO was placed inside the Ho:YAG oscillator. Under the Q-switched repetition frequency of 5kHz, the maximum output power of the mid-infrared laser was 1.5W. The optical-optical conversion efficiency of the 1908nm laser to the mid-infrared laser was 7.5%, and the slope efficiency was 15%. The two central wavelengths of mid-infrared laser were located at 3.9~4.05μm and 4.35~4.5μm respectively. The pulse width was 29.9ns and the single-pulse energy was 0.3mJ.
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