An un-forgotten classic: the nitro-Mannich reaction between nitrones and silyl nitronates catalysed by B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>.
Guerzoni, Michael G.; van Ingen, Yara; Babaahmadi, Rasool; Wirth, Thomas; Richards, Emma; Melen, Rebecca L.; Chemical science 15 (2024) 2648–2654; doi:10.1039/d3sc05672d

data_1570770
_publ_section_title
;
 An un-forgotten classic: the nitro-Mannich reaction between nitrones and
 silyl nitronates catalysed by B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>.
;
_journal_issue                   7
_journal_name_full               'Chemical science'
_journal_page_first              2648
_journal_page_last               2654
_journal_paper_doi               10.1039/d3sc05672d
_journal_volume                  15
_journal_year                    2024
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C21 H26 N2 O4 Si'
_chemical_formula_sum            'C21 H26 N2 O4 Si'
_chemical_formula_weight         398.53
_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     intrinsic
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2018/3
_audit_update_record
;
2023-10-16 deposited with the CCDC.	2023-12-29 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   9.9467(4)
_cell_length_b                   10.7574(6)
_cell_length_c                   19.8365(9)
_cell_measurement_reflns_used    5764
_cell_measurement_temperature    200(2)
_cell_measurement_theta_max      29.3100
_cell_measurement_theta_min      4.0940
_cell_volume                     2122.52(17)
_computing_cell_refinement       'CrysAlisPro 1.171.42.90a (Rigaku OD, 2023)'
_computing_data_collection       'CrysAlisPro 1.171.42.90a (Rigaku OD, 2023)'
_computing_data_reduction        'CrysAlisPro 1.171.42.90a (Rigaku OD, 2023)'
_computing_molecular_graphics    'ORTEP, Mercury'
_computing_structure_refinement  'SHELXL-2018/3 (Sheldrick, 2018)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_temperature      200(2)
_diffrn_measured_fraction_theta_full 0.996
_diffrn_measured_fraction_theta_max 0.865
_diffrn_measurement_device_type  'micro-focus sealed X-ray tube'
_diffrn_measurement_method       'w/ scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0150
_diffrn_reflns_av_unetI/netI     0.0273
_diffrn_reflns_Laue_measured_fraction_full 0.996
_diffrn_reflns_Laue_measured_fraction_max 0.865
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            9161
_diffrn_reflns_point_group_measured_fraction_full 0.997
_diffrn_reflns_point_group_measured_fraction_max 0.818
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         29.823
_diffrn_reflns_theta_min         3.464
_diffrn_source                   'micro-focus sealed X-ray tube'
_exptl_absorpt_coefficient_mu    0.139
_exptl_absorpt_correction_T_max  1.000
_exptl_absorpt_correction_T_min  0.707
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.42.90a (Rigaku Oxford Diffraction, 2023)
Numerical absorption correction based on gaussian integration over
a multifaceted crystal model
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.247
_exptl_crystal_description       blocks
_exptl_crystal_F_000             848
_exptl_crystal_size_max          1.000
_exptl_crystal_size_mid          0.439
_exptl_crystal_size_min          0.173
_refine_diff_density_max         0.217
_refine_diff_density_min         -0.193
_refine_diff_density_rms         0.035
_refine_ls_abs_structure_details
;
 Flack x determined using 1693 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.44(4)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.030
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     257
_refine_ls_number_reflns         4976
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.030
_refine_ls_R_factor_all          0.0418
_refine_ls_R_factor_gt           0.0354
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0357P)^2^+0.5160P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0816
_refine_ls_wR_factor_ref         0.0858
_reflns_Friedel_coverage         0.679
_reflns_Friedel_fraction_full    0.999
_reflns_Friedel_fraction_max     0.757
_reflns_number_gt                4488
_reflns_number_total             4976
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d3sc05672d2.cif
_cod_data_source_block           RM2339_a
_cod_depositor_comments
'Adding full bibliography for 1570770--1570774.cif.'
_cod_database_code               1570770
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_min   0.874
_shelx_estimated_absorpt_t_max   0.976
_shelx_res_checksum              78208