Rhodium-catalyzed carbonylation of acetylenes was studied. Under water-gas shift reaction conditions, internal acetylenes are selectively carbonylated to 3,4-disubstituted furan-2(5H)-ones (2). Use of D20 gave 5,5-dideuteriofuran-2(5H)-one (31, which indicates that the hydrogen comes from water. Use of molecular hydrogen in place of water gave hydroxymethylated product 4 and stilbene 5, and no furanone was obtained, indicating that water-gas shift reaction conditions are indespensable for the formation of furanones. As catalysts, rhodium carbonyl clusters such as Rh4(C0)12 and Rh&CO),6 are the best among the transition-metal complexes tested. The presence of amines is essential for the selective synthesis of furanones. Effects of additives, solvents, and the pressure of carbon monoxide were examined.
The reactivities of 1-buten-3-yne derivatives toward hydroformylation were studied using a rhodium catalyst. Unexpectedly, cyclopentenone derivatives were obtained in moderate yields together with formylsubstituted dienes and unsaturated lactones. This reaction offers a new method for the catalytic synthesis of cyclopentenones. A mechanism for the cyclic carbonylation of enynes is also discussed.
Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin.
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