Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• ketones 42 [37]. With this transformation polysubstituted cyclohexanes 43 bearing four consecutive stereocenters are afforded through efficient one-pot cyclization with good yields (43–95%) and with high enantioselectivities (80–97% ee) (Scheme 15). In general, 1-azadienes 14 with different substitution

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

• Lukáš Ďurina,
• Anna Ďurinová,
• František Trejtnar,
• Ľuboš Janotka,
• Lucia Messingerová,
• Jana Doháňošová,
• Ján Moncol and
• Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

• racemic codonopsinol B (1) and its N-nor-methyl analogue 2 starting from achiral materials. Four consecutive stereocenters in the target molecules were accomplished sequentially by the organocatalytic aza-Michael addition of N-Cbz-protected hydroxylamine to (E)-4-methoxycinnamaldehyde, the trans

Construction of highly enantioenriched spirocyclopentaneoxindoles containing four consecutive stereocenters via thiourea-catalyzed asymmetric Michael–Henry cascade reactions

• Yonglei Du,
• Jian Li,
• Kerong Chen,
• Chenglin Wu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2017, 13, 1342–1349, doi:10.3762/bjoc.13.131

• spirocyclopentaneoxindoles. Keywords: asymmetric synthesis; four consecutive stereocenters; Michael–Henry cascade reactions; spirocyclopentaneoxindoles; thioureas; Introduction The spirocyclic oxindole core represents an important scaffold that is encountered frequently in many biologically active molecules and natural

• asymmetric catalytic synthesis of saturated spirocyclopentaneoxindoles containing four consecutive stereocenters with 3-substituted oxindoles and nitrovinylacetamide using a bifunctional thiourea catalyst in good yields (up to 95%) with excellent diastereoselectivity (up to 3:97) and enantioselectivity (up

• the catalyst d. The absolute configuration of 3g was determined by X-ray analysis (see Supporting Information File 1, Figure S1). Conclusion We have developed a highly efficient and practical strategy for a single step construction of saturated spirocyclopentaneoxindoles containing four consecutive