Asymmetric organocatalytic synthesis of chiral homoallylic amines

• Nikolay S. Kondratyev and
• Andrei V. Malkov

Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201

• -catalysed hydrogen atom transfer deracemisation [45]. Chiral PA-catalysed [1,3]-rearrangement of ene-aldimines [46].

• trifluoromethylated amine 146 was obtained in 75% yield and 83% ee. The scope of this reaction is yet to be explored. In 2022, Momiyama and co-workers presented a novel synthetic approach towards enantioenriched homoallylic amines 150 that bear a chiral centre on the β-carbon, based on an asymmetric [1,3

• ]-rearrangement of ene-aldimines 149, catalysed by the BINOL-derived chiral phosphoric acid (CPA) (R)-151 (Scheme 31) [46]. DFT computational analysis suggested that the reaction proceeds via a complex cascade that involves the fragmentation of ene-aldimine 149 to form an imine methylene cation, which in turn

The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

• Katarzyna Włodarczyk,
• Piotr Borowski and
• Marek Stankevič

Beilstein J. Org. Chem. 2020, 16, 88–105, doi:10.3762/bjoc.16.11

• reaction. In the presence of a Brønsted acid, mainly [1,3]-rearrangement is observed, whereas a Lewis acid catalyzes the [1,4]-sulfur migration. To gain insight into the mechanism of these transformations, the stereochemistry of these rearrangements have been tested, along with the conduction of some

• rearrangement in the presence of Brønsted-acidic H2SO4 afforded only minor amounts of S-acylated γ-mercaptoalkylphosphine oxide 68, but the enantiomeric excess was even higher than in the substrate. This suggested that the [1,3]-rearrangement was stereospecific in the presence of Brønsted acid, whereas the [1,4

Cationic cobalt-catalyzed [1,3]-rearrangement of N-alkoxycarbonyloxyanilines

• Itaru Nakamura,
• Mao Owada,
• Takeru Jo and
• Masahiro Terada

Beilstein J. Org. Chem. 2018, 14, 1972–1979, doi:10.3762/bjoc.14.172

• labelling experiments indicate that the rearrangement of the alkoxycarbonyloxy group proceeds in [1,3]-manner. In this article, we discuss the overall picture of the cobalt-catalysed [1,3]-rearrangement reaction including details of the reaction conditions and substrate scope. Keywords: anilines; cobalt

• mechanistic studies revealed that the rearrangement of the alkoxycarbonyloxy group proceeded in an unprecedented [1,3]-manner (Scheme 2c). In this article, we describe the overall picture of the intriguing [1,3]-rearrangement reaction, particularly the detail of the reaction, which were not sufficiently

• suggest that the C–O bond would form prior to cleavage of the C–H bond in the [1,3]-rearrangement reaction. Due to the fact that the reaction of 1a in the presence of tri- and tetravalent cationic metal catalysts afforded the para-isomer 3a as a major product (Table 1, entries 14–18), the reaction of

Further exploration of the heterocyclic diversity accessible from the allylation chemistry of indigo

• Alireza Shakoori,
• John B. Bremner,
• Mohammed K. Abdel-Hamid,
• Anthony C. Willis,
• Rachada Haritakun and
• Paul A. Keller

Beilstein J. Org. Chem. 2015, 11, 481–492, doi:10.3762/bjoc.11.54

• 1,3-rearrangement process. The N-allylisatins observed [4] are likely to be formed by oxidative cleavage processes as previously reported [4][11]. Control of the branch points in the overall base-catalysed cascade allylation reactions with indigo is clearly important in achieving practical synthetic

Gold-catalyzed intermolecular coupling of sulfonylacetylene with allyl ethers: [3,3]- and [1,3]-rearrangements

• Jungho Jun,
• Hyu-Suk Yeom,
• Jun-Hyun An and
• Seunghoon Shin

Beilstein J. Org. Chem. 2013, 9, 1724–1729, doi:10.3762/bjoc.9.198

• ]-rearrangement products through the formation of a tight ion–dipole pair. Keywords: gold catalysis; intermolecular coupling; [1,3]-rearrangement; [3,3]-sigmatropic rearrangement; sulfonylacetylene; Introduction Homogeneous gold catalysis has been established during the last decade as a prominent tool in

• bulky substituent at R1. The substituents on the allyl unit also affected the reaction significantly. A cyclohexyl group as γ-substituent (R2) led to a slower reaction, delivering 3d only in 54% yield, with a concomitant decrease in the ratio of [3,3]- versus [1,3]-rearrangement products, while primary

• alkyl groups as R2 were well accommodated (Table 2, entries 4–6). These indicated that a steric crowding in the proposed [3,3]-sigmatropic rearrangement transition state (Path A in Scheme 1) resulted in a sluggish reaction, but affected the competitive [1,3]-rearrangement less severely. It is noteworthy

Alkoxide-induced ring opening of bicyclic 2-vinylcyclobutanones: A convenient synthesis of 2-vinyl-substituted 3-cycloalkene-1-carboxylic acid esters

• Xiufang Ji,
• Zhiming Li,
• Quanrui Wang and
• Andreas Goeke

Beilstein J. Org. Chem. 2012, 8, 650–657, doi:10.3762/bjoc.8.72

• [1,2]- and [1,3]-acyl migration of 2-vinylcyclobutanones, leading to cyclopentenones or cyclohexenones, respectively [15]. Danheiser and co-workers reported an oxyanion-accelerated [1,3]-rearrangement of in situ reduced 2-vinylcyclobutanones, by applying mixtures of LiBu3BH-MeLi and HMPT to give