The intramolecular1,3-chiralitytransferreaction of chiral amino alcohols 1 with 99% ee was developed to construct chiral 1-substituted tetrahydroisoquinoline 2. Bi(OTf)3 (10 mol %)-catalyzed cyclization of 1 (R = H) afforded (S)-1-(E)-propenyl tetrahydroisoquinoline 2 (R = H) in 83% yield with a ratio of 98:2. The stereochemistry at the newly formed chiralcenter was produced by a syn SN2′-type
开展了手性氨基醇1与99%ee的分子内1,3-手性转移反应,构建了手性1取代的四氢异喹啉2。Bi(OTf)3(10 mol%)催化1的环化反应(R = H)得到(S)-1-(E)-丙烯基四氢异喹啉2(R = H),产率为83:2,比率为98:2 。在新形成的手性中心的立体化学是通过syn S N 2'型过程产生的。在该反应中,苯环1上的取代基显着影响反应性和选择性。提出了合理的反应机理。
Synthesis of Polysubstituted Naphthalenes by a Hydride Shift Mediated C–H Bond Functionalization/Aromatization Sequence
作者:Koutarou Amano、Tomoko Kawasaki-Takasuka、Keiji Mori
DOI:10.1021/acs.orglett.3c04355
日期:2024.3.8
A synthetic strategy for forming multisubstituted naphthalenes based on hydride shift mediated C(sp3)–H bond functionalization was developed. This strategy consists of three successive transformations: (1) an intramolecular hydride shift mediated C(sp3)–H bond functionalization; (2) a decarboxylative fragmentation; and (3) an oxidation reaction. When benzylidene malonates having a 2-alkoxyethyl group
Divergent synthesis of multi-substituted phenanthrenes via an internal redox reaction/ring expansion sequence
作者:Ryosei Koyama、Masahiro Anada、Shunsuke Sueki、Kosho Makino、Tatsuhiro Kojima、Tomoko Kawasaki-Takasuka、Keiji Mori
DOI:10.1039/d4cc00797b
日期:——
internal redox reaction/ringexpansion sequence. The interesting feature of the present system is that it allows for the divergent synthesis of the target skeleton depending on the selected Lewis acid catalyst. When benzylidene malonates with a cyclic structure at the ortho-position were treated with BF3·OEt2, three sequential processes (internal redox reaction/elimination of the alkoxy group/ring expansion)
A rhodium-catalyzed [4 + 2] cycloaddition of ynamines and 2-(cyanomethyl)phenylboronates has been developed, leading to efficient and excellent regioselective synthesis of valuable indole-linked aromatic compounds in a concise and flexible approach. Interestingly, this strategy was successful in the construction of C···N axially chiral indoles with high enantiocontrol by the introduction of a new phosphoramidite