Chiral amine-urea mediated asymmetric inverse-electron-demand cycloadditions of cyclic nitrones with <i>o</i>-hydroxystyrenes.
Toda, Yasunori; Soma, Yukinao; Horiba, Nobuteru; Koyama, Masato; Iwakuma, Fumiya; Matsumoto, Suguru; Sukegawa, Kimiya; Kikuchi, Ayaka; Suga, Hiroyuki; Organic & biomolecular chemistry 24 (2026) 1006–1010; doi:10.1039/d5ob01989c

data_7160932
_publ_section_title
;
 Chiral amine-urea mediated asymmetric inverse-electron-demand
 cycloadditions of cyclic nitrones with <i>o</i>-hydroxystyrenes.
;
_journal_issue                   5
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              1006
_journal_page_last               1010
_journal_paper_doi               10.1039/d5ob01989c
_journal_volume                  24
_journal_year                    2026
_chemical_absolute_configuration syn
_chemical_formula_sum            'C18 H19 N O3'
_chemical_formula_weight         297.34
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_update_record
;
2025-10-29 deposited with the CCDC.	2026-01-09 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.1857(10)
_cell_length_b                   7.6402(11)
_cell_length_c                   27.948(4)
_cell_measurement_reflns_used    37
_cell_measurement_temperature    93.(2)
_cell_measurement_theta_max      14.4858
_cell_measurement_theta_min      2.7740
_cell_volume                     1534.4(4)
_computing_cell_refinement       'APEX2 v2010.11-3 (Bruker AXS)'
_computing_data_collection       'Bruker Instrument Service v2010.11.0.0'
_computing_data_reduction        'SAINT V7.68A (Bruker AXS, 2009)'
_computing_molecular_graphics    'XSHELL V6.3.1 (Bruker AXS)'
_computing_publication_material  'Generate Report (Bruker AXS)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      93.(2)
_diffrn_detector_area_resol_mean 8.3333
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker D8 goniometer'
_diffrn_measurement_method       'omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.1107
_diffrn_reflns_av_sigmaI/netI    0.0843
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       33
_diffrn_reflns_limit_l_min       -33
_diffrn_reflns_number            14849
_diffrn_reflns_theta_full        25.05
_diffrn_reflns_theta_max         25.05
_diffrn_reflns_theta_min         1.46
_diffrn_source                   'sealed tube'
_exptl_absorpt_coefficient_mu    0.088
_exptl_absorpt_correction_T_max  0.99
_exptl_absorpt_correction_T_min  0.89
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS V2008/1 (Bruker AXS)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.287
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             632
_exptl_crystal_size_max          0.350
_exptl_crystal_size_mid          0.140
_exptl_crystal_size_min          0.090
_refine_diff_density_max         0.187
_refine_diff_density_min         -0.177
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -3.(2)
_refine_ls_extinction_coef       0.0140(16)
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   0.997
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     202
_refine_ls_number_reflns         2725
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.997
_refine_ls_R_factor_all          0.1233
_refine_ls_R_factor_gt           0.0539
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0432P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0934
_refine_ls_wR_factor_ref         0.1166
_reflns_number_gt                1556
_reflns_number_total             2725
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            d5ob01989c2.cif
_cod_data_source_block           I
_cod_database_code               7160932