N-Heterocyclic carbenes as chiral Brønsted base catalysts: a highly diastereo- and enantioselective 1,6-addition reaction.
Santra, Surojit; Porey, Arka; Jana, Barun; Guin, Joyram; Chemical science 9 (2018) 6446–6450; doi:10.1039/c8sc02138d

data_1549640
_publ_section_title
;
 N-Heterocyclic carbenes as chiral Br\/onsted base catalysts: a highly
 diastereo- and enantioselective 1,6-addition reaction.
;
_journal_issue                   30
_journal_name_full               'Chemical science'
_journal_page_first              6446
_journal_page_last               6450
_journal_paper_doi               10.1039/c8sc02138d
_journal_volume                  9
_journal_year                    2018
_chemical_absolute_configuration ad
_chemical_formula_sum            'C49 H48 Br N O3'
_chemical_formula_weight         778.79
_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'
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/6
_audit_update_record
;
2018-03-21 deposited with the CCDC.
2018-07-02 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   10.1180(10)
_cell_length_b                   14.0353(14)
_cell_length_c                   28.194(3)
_cell_measurement_reflns_used    9989
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      25.14
_cell_measurement_theta_min      2.48
_cell_volume                     4003.8(7)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
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_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
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_computing_structure_solution    'SHELXS-97 (Sheldrick 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.1313
_diffrn_reflns_av_unetI/netI     0.0999
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       10
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_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       34
_diffrn_reflns_limit_l_min       -34
_diffrn_reflns_number            42021
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.999
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.691
_diffrn_reflns_theta_min         2.478
_exptl_absorpt_coefficient_mu    1.070
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.292
_exptl_crystal_description       block
_exptl_crystal_F_000             1632
_exptl_crystal_size_max          0.080
_exptl_crystal_size_mid          0.040
_exptl_crystal_size_min          0.020
_refine_diff_density_max         1.376
_refine_diff_density_min         -0.550
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_refine_ls_abs_structure_details
;
 Flack x determined using 2283 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.075(9)
_refine_ls_extinction_method     none
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_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
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_refine_ls_number_reflns         7602
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.040
_refine_ls_R_factor_all          0.0714
_refine_ls_R_factor_gt           0.0537
_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^)+(0.0620P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1295
_refine_ls_wR_factor_ref         0.1392
_reflns_Friedel_coverage         0.782
_reflns_Friedel_fraction_full    0.999
_reflns_Friedel_fraction_max     0.999
_reflns_number_gt                6201
_reflns_number_total             7602
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c8sc02138d2.cif
_cod_data_source_block           data
_cod_depositor_comments
'Adding full bibliography for 1549640--1549642.cif.'
_cod_database_code               1549640
_shelx_estimated_absorpt_t_min   0.919
_shelx_estimated_absorpt_t_max   0.979
_shelxl_version_number           2014/6
_shelx_res_checksum              95002