Asymmetric Hydrogenation of α-Primary and Secondary Amino Ketones: Efficient Asymmetric Syntheses of (−)-Arbutamine and (−)-Denopamine
作者:Gao Shang、Duan Liu、Scott E. Allen、Qin Yang、Xumu Zhang
DOI:10.1002/chem.200700594
日期:2007.9.17
Two beta-receptor agonists (-)-denopamine and (-)-arbutamine were prepared in good yields and enantioselectivities by asymmetrichydrogenation of unprotected aminoketones for the first time by using Rh catalysts bearing electron-donating phosphine ligands. A series of alpha-primary and secondaryaminoketones were synthesized and hydrogenated to produce various 1,2-amino alcohols in good yields and
Synthesis of Trisubstituted Oxazoles via Aryne Induced [2,3] Sigmatropic Rearrangement–Annulation Cascade
作者:Rahul N. Gaykar、Shiksha Deswal、Avishek Guin、Subrata Bhattacharjee、Akkattu T. Biju
DOI:10.1021/acs.orglett.2c01379
日期:2022.6.17
transition-metal-free, [2,3] sigmatropic rearrangement–annulation cascade of 2-substituted thio/amino acetonitriles with arynes allowing the synthesis of 2,4,5-trisubstituted oxazoles under mild conditions has been demonstrated. The key sulfur/nitrogen ylides were generated by the initial S/N arylation followed by proton transfer, which was followed by the selective [2,3] sigmatropicrearrangement involving the
Synthesis of polycarpine, a cytotoxic sulfur-containing alkaloid from the ascidian Polycarpa aurata, and related compounds
作者:Oleg S. Radchenko、Vyacheslav L. Novikov、Richard H. Willis、Peter T. Murphy、George B. Elyakov
DOI:10.1016/s0040-4039(97)00668-0
日期:1997.5
Polycarpine 1, a highly cytotoxic marine natural product, has been synthesized in three steps from p-methoxyphenacyl bromide 4 in 57% overall yield. The key reaction for construction of the symmetrically substituted disulfide linkage of polycarpine is the treatment of 2-amino-4-(4-methoxyphenyl)-1-methylimidazole 17 with S2Cl2 in acetic acid. In a similar way ten related compounds, including three thiazole analogues, have been prepared. Most of them exhibit high cytotoxic activities against an array of human cancer cell lines. (C) 1997 Elsevier Science Ltd.