Synthesis of planar chiral biferrocenes by iridium-catalyzed [2+2+2] cycloadition of a biferrocene-linked diyne with nitriles: asymmetric desymmetrization and kinetic resolution
Sawano, Takahiro; Murata, Kayo; Suzaki, Tomoaki; Urasawa, Kazuki; Kobayashi, Manami; Aso, Ryota; Ozasa, Kazuki; Ishikawa, Eri; Takeuchi, Ryo; Chemical Communications  (2026) –; doi:10.1039/D6CC00435K

data_7135701
_publ_section_title
;
 Synthesis of planar chiral biferrocenes by iridium-catalyzed [2+2+2]
 cycloaddition of biferrocene-linked diynes with nitriles: asymmetric
 desymmetrization and kinetic resolution.
;
_journal_issue                   33
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              8451
_journal_page_last               8455
_journal_paper_doi               10.1039/d6cc00435k
_journal_volume                  62
_journal_year                    2026
_chemical_absolute_configuration 'CHOOSE rm ad rmad syn or unk'
_chemical_formula_moiety         'C33 H27 Fe2 N'
_chemical_formula_sum            'C33 H27 Fe2 N'
_chemical_formula_weight         549.28
_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
;
2026-01-12 deposited with the CCDC.	2026-04-02 downloaded from the CCDC.
;
_cell_angle_alpha                90.0000
_cell_angle_beta                 90.0000
_cell_angle_gamma                90.0000
_cell_formula_units_Z            4
_cell_length_a                   11.290(4)
_cell_length_b                   12.851(3)
_cell_length_c                   16.608(4)
_cell_measurement_reflns_used    23149
_cell_measurement_temperature    173
_cell_measurement_theta_max      27.46
_cell_measurement_theta_min      3.04
_cell_volume                     2409.6(12)
_computing_cell_refinement       'RAPID AUTO'
_computing_data_collection       'RAPID AUTO (Rigaku, ????)'
_computing_data_reduction        'RAPID AUTO'
_computing_molecular_graphics    'CrystalStructure 4.3'
_computing_publication_material  'CrystalStructure 4.3 (Rigaku, 2019)'
_computing_structure_refinement  'SHELXL Version 2018/3 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXT Version 2018/2 (Sheldrick, 2014)'
_diffrn_ambient_temperature      173
_diffrn_detector_area_resol_mean 10.000
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Rigaku R-AXIS RAPID'
_diffrn_measurement_method       \w
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71075
_diffrn_reflns_av_R_equivalents  0.0312
_diffrn_reflns_av_unetI/netI     0.0237
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            23724
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.997
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.460
_diffrn_reflns_theta_min         3.045
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    1.227
_exptl_absorpt_correction_T_max  0.885
_exptl_absorpt_correction_T_min  0.818
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   'NUMABS (Rigaku, 1999)'
_exptl_crystal_colour            orange
_exptl_crystal_density_diffrn    1.514
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1136.00
_exptl_crystal_recrystallization_method 'Re-crystallisation from solvent'
_exptl_crystal_size_max          0.600
_exptl_crystal_size_mid          0.600
_exptl_crystal_size_min          0.100
_refine_diff_density_max         0.24
_refine_diff_density_min         -0.39
_refine_ls_abs_structure_details
;
 Flack x determined using 2299 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.005(4)
_refine_ls_extinction_coef       0.0013(4)
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.069
_refine_ls_hydrogen_treatment    refxyz
_refine_ls_number_parameters     434
_refine_ls_number_reflns         5496
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0196
_refine_ls_R_factor_gt           0.0191
_refine_ls_shift/su_max          0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w = 1/[\s^2^(Fo^2^)+(0.0369P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0516
_refine_ls_wR_factor_ref         0.0518
_reflns_Friedel_coverage         0.775
_reflns_Friedel_fraction_full    0.998
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                5364
_reflns_number_total             5496
_reflns_threshold_expression     F^2^>2.0\s(F^2^)
_cod_data_source_file            d6cc00435k2.cif
_cod_data_source_block           SawanoKayo197A
_cod_depositor_comments
'Adding full bibliography for 7135696--7135704.cif.'
_cod_original_cell_volume        2409.6(11)
_cod_database_code               7135701
_shelx_res_checksum              67936