Unusual C-2 selectivity of Grignard additions to <i>N</i>-Boc-protected isatin 3-imines.
Plakas, Alexandra Mary; Butsi, Kamogelo Rosinah; Lala, Sahil; van Zyl, Robyn Lynne; Fernandes, Manuel Antonio; Ntsimango, Songeziwe; Bode, Moira Leanne; Rousseau, Amanda Louise; Organic & biomolecular chemistry 24 (2026) 1672–1677; doi:10.1039/d5ob01909e

data_7160942
_publ_section_title
;
 Unusual C-2 selectivity of Grignard additions to <i>N</i>-Boc-protected
 isatin 3-imines.
;
_journal_issue                   8
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              1672
_journal_page_last               1677
_journal_paper_doi               10.1039/d5ob01909e
_journal_volume                  24
_journal_year                    2026
_chemical_formula_moiety         'C28 H29 Br N2 O4'
_chemical_formula_sum            'C28 H29 Br N2 O4'
_chemical_formula_weight         537.44
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     dual
_audit_creation_date             2023-11-29
_audit_creation_method
;
Olex2 1.5
(compiled 2023.08.24 svn.re1ec1418 for OlexSys, GUI svn.r6817)
;
_audit_update_record
;
2025-12-04 deposited with the CCDC.	2026-01-28 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 103.055(4)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   14.1456(18)
_cell_length_b                   17.8889(19)
_cell_length_c                   10.4103(13)
_cell_measurement_reflns_used    5904
_cell_measurement_temperature    173.00
_cell_measurement_theta_max      25.95
_cell_measurement_theta_min      2.31
_cell_volume                     2566.2(5)
_computing_cell_refinement       'SAINT V8.40B (?, 2016)'
_computing_data_reduction        'SAINT V8.40B (?, 2016)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2018/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT  (Sheldrick, 2015)'
_diffrn_ambient_temperature      173.00
_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  0.1113
_diffrn_reflns_av_unetI/netI     0.0554
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       18
_diffrn_reflns_limit_h_min       -18
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       -22
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            44998
_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         27.000
_diffrn_reflns_theta_min         2.277
_diffrn_source_current           1.4
_diffrn_source_power             0.07
_diffrn_source_voltage           50.0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    1.638
_exptl_absorpt_correction_T_max  0.7457
_exptl_absorpt_correction_T_min  0.5784
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1621 before and 0.1053 after correction.
The Ratio of minimum to maximum transmission is 0.7756.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.391
_exptl_crystal_description       needle
_exptl_crystal_F_000             1112
_exptl_crystal_recrystallization_method 'Re-crystallisation from solvent: DCM'
_exptl_crystal_size_max          0.478
_exptl_crystal_size_mid          0.167
_exptl_crystal_size_min          0.052
_refine_diff_density_max         0.332
_refine_diff_density_min         -0.561
_refine_diff_density_rms         0.068
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.034
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     324
_refine_ls_number_reflns         5591
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.034
_refine_ls_R_factor_all          0.0702
_refine_ls_R_factor_gt           0.0410
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0230P)^2^+1.7451P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0783
_refine_ls_wR_factor_ref         0.0900
_reflns_Friedel_coverage         0.000
_reflns_number_gt                4098
_reflns_number_total             5591
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5ob01909e2.cif
_cod_data_source_block           Compound_3e_21mbb_mbrack_mandyamp_k4_0f
_cod_depositor_comments
'Adding full bibliography for 7160941--7160942.cif.'
_cod_database_code               7160942
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_max   0.920
_shelx_estimated_absorpt_t_min   0.508
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Secondary CH2 refined with riding coordinates:
 C10(H10A,H10B), C11(H11A,H11B)
2.b Aromatic/amide H refined with riding coordinates:
 C3(H3A), C4(H4), C5(H5), C6(H6), C13(H13), C14(H14), C16(H16), C17(H17),
 C24(H24), C25(H25), C27(H27), C28(H28)
2.c Idealised Me refined as rotating group:
 C18(H18A,H18B,H18C), C20(H20A,H20B,H20C), C21(H21A,H21B,H21C), C22(H22A,H22B,
 H22C)
;
_shelx_res_checksum              59011
_shelx_hkl_checksum              15814
_olex2_submission_special_instructions 'No special instructions were received'