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Calcium-Impregnated Silica Gel as a Reducing Agent in Domino Reactions for Bond Formations
Khagendra Prasad Bohara1, Animesh Roy1, Jih Ru Hwu1
1Department of Chemistry and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 300, Taiwan.
None:
The reagent Ca@SiO2 was obtained by impregnation of silica gel with calcium metal. The presence of Ca@SiO2 allowed aldehydes to condense with ketones in 2-MeTHF, which resulted in α,β-unsaturated cyclohexenones in 73-90% yields through a radical domino process. Furthermore, Ca@SiO2 was used to induce a Darzens reaction for the efficient production of α-keto trans-epoxides from benzaldehydes and α-bromo ketones. Being a free-flowing powder, Ca@SiO2 was easy to handle and facilitated chemoselectivity among many functional groups.
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