Photocatalytic Chemodivergent Synthesis of <i>α</i>‐<i>gem</i>‐Dihalovinyl Ketones and Chromen‐2‐Ones from Monoalkynes
Zi‐Yang Xu, Yin‐Ping Liu, Xin Liu, Rong Fu, Wen‐Juan Hao, Shu‐Jiang Tu, Bo Jiang
Abstract
Abstract A general photocatalytic substrate‐controlled chemodivergent strategy starting from monoalkynes with polyhalomethanes such as BrCCl 3 and CBr 4 was develop, enabling Kharasch‐type addition/nucleophilic substitution cascade to selectively produce α ‐ gem ‐dihalovinyl ketones and chromen‐2‐ones with moderate to good yields. Use of monoalkynes without additional nucleophilic sites furnished α ‐ gem ‐dihalovinyl ketones through a Kharasch‐type addition and intermolecular allylic substitution cascade whereas the latter transformation of 2‐ethynylphenols allowed the full breaking of carbon‐halogen bonds of BrCX 3 to access functionalized chromen‐2‐ones. The late‐stage application of these resulting α ‐ gem ‐dihalovinyl ketones demonstrates the versatility of their derivatization. magnified image