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_7135702
_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 ad
_chemical_formula_moiety         'C26 H22 Fe2'
_chemical_formula_sum            'C26 H22 Fe2'
_chemical_formula_weight         446.13
_space_group_crystal_system      monoclinic
_space_group_IT_number           5
_space_group_name_Hall           'C 2y'
_space_group_name_H-M_alt        'C 1 2 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2025-10-13
_audit_creation_method
;
Olex2 1.5-ac6-017
(compiled 2024.02.01 svn.r2f8d729c for Rigaku Oxford Diffraction, GUI svn.r6920)
;
_audit_update_record
;
2026-01-12 deposited with the CCDC.	2026-04-02 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 106.368(3)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   18.8836(5)
_cell_length_b                   7.0009(2)
_cell_length_c                   15.6731(5)
_cell_measurement_reflns_used    6444
_cell_measurement_temperature    100.00(10)
_cell_measurement_theta_max      78.4810
_cell_measurement_theta_min      2.9110
_cell_volume                     1988.04(10)
_computing_cell_refinement       'CrysAlisPro 1.171.43.108a (Rigaku OD, 2024)'
_computing_data_collection
'CrysAlisPro system (CCD 43.108a 64-bit (release 14-02-2024))'
_computing_data_reduction        'CrysAlisPro 1.171.43.108a (Rigaku OD, 2024)'
_computing_molecular_graphics    'Olex2 1.5-ac6-017 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5-ac6-017 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2018/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      100.00(10)
_diffrn_detector                 'Hybrid Pixel Array Detector'
_diffrn_detector_area_resol_mean 10.0000
_diffrn_detector_type            HyPix
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.955
_diffrn_measurement_details
;
List of Runs (angles in degrees, time in seconds):

  # Type    Start    End  Width  t~exp~   \w     \q     \k     \f   Frames
  1  \w    -52.00 -21.00   0.50    0.43    --  -91.75  57.00-150.00   62
  2  \w    -20.00  18.00   0.50    0.11    --  -48.61  19.00 -60.00   76
  3  \w    -60.00 -20.00   0.50    0.43    --  -91.75  57.00   0.00   80
  4  \w    -66.00 -26.00   0.50    0.43    --  -91.75  57.00 -30.00   80
  5  \w    -73.00   9.00   0.50    0.11    --  -48.61  82.00   7.00  164
  6  \w    -58.00 -31.00   0.50    0.43    --  -91.75  82.00   7.00   54
  7  \w   -133.00 -79.00   0.50    0.43    --  -91.75 -19.00 120.00  108
  8  \w   -131.00 -89.00   0.50    0.43    --  -91.75 -19.00  90.00   84
  9  \w   -158.00-126.00   0.50    0.43    --  -91.75 -57.00 -60.00   64
 10  \w   -109.00 -79.00   0.50    0.43    --  -91.75 -57.00-180.00   60
 11  \w   -153.00-123.00   0.50    0.43    --  -91.75 -57.00-180.00   60
 12  \w   -156.00-107.00   0.50    0.43    --  -91.75 -82.00-113.00   98
 13  \w   -132.00 -93.00   0.50    0.43    --  -91.75 -99.00-150.00   78
 14  \w   -114.00 -76.00   0.50    0.11    --  -48.61-125.00 -60.00   76
 15  \w   -116.00 -85.00   0.50    0.11    --  -48.61-125.00 -30.00   62
 16  \w   -139.00 -77.00   0.50    0.43    --  -91.75-125.00 150.00  124
 17  \w   -159.00 -90.00   0.50    0.43    --  -91.75 -99.00  30.00  138
 18  \w   -113.00 -87.00   0.50    0.43    --  -91.75 -99.00 -30.00   52
 19  \w     37.00 121.00   0.50    0.11    --   48.61  57.00  60.00  168
 20  \w    142.00 172.00   0.50    0.43    --  113.25  38.00  60.00   60
 21  \w    106.00 136.00   0.50    0.43    --  113.25  38.00  60.00   60
 22  \w    101.00 136.00   0.50    0.43    --  113.25  38.00 -30.00   70
 23  \w    153.00 178.00   0.50    0.43    --  113.25  38.00 -30.00   50
 24  \w    121.00 146.00   0.50    0.43    --  113.25 125.00  60.00   50
 25  \w    125.00 174.00   0.50    0.43    --  113.25  82.00   7.00   98
 26  \w    -26.00  -1.00   0.50    0.11    --   48.61 -19.00-150.00   50
 27  \w     80.00 106.00   0.50    0.43    --  113.25-125.00  90.00   52
 28  \w     50.00 111.00   0.50    0.43    --  113.25-125.00 150.00  122
 29  \w     45.00  71.00   0.50    0.43    --  113.25-125.00  90.00   52
 30  \w     51.00 104.00   0.50    0.43    --  113.25 -99.00 -90.00  106
 31  \w     47.00 104.00   0.50    0.43    --  113.25 -99.00-150.00  114
 32  \w     80.00 105.00   0.50    0.43    --  113.25 -99.00-180.00   50
 33  \w     86.00 128.00   0.50    0.43    --  113.25 -82.00-113.00   84
 34  \w     41.00  69.00   0.50    0.11    --   48.61 -82.00-113.00   56
 35  \w    -19.00  36.00   0.50    0.11    --   48.61 -82.00-113.00  110
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'XtaLAB Synergy, Dualflex, HyPix'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      -0.0039972000
_diffrn_orient_matrix_UB_12      -0.1142509000
_diffrn_orient_matrix_UB_13      -0.0852144000
_diffrn_orient_matrix_UB_21      -0.0514821000
_diffrn_orient_matrix_UB_22      0.1527471000
_diffrn_orient_matrix_UB_23      -0.0557627000
_diffrn_orient_matrix_UB_31      0.0675345000
_diffrn_orient_matrix_UB_32      0.1098107000
_diffrn_orient_matrix_UB_33      -0.0111743000
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0337
_diffrn_reflns_av_unetI/netI     0.0371
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.955
_diffrn_reflns_limit_h_max       24
_diffrn_reflns_limit_h_min       -20
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            10418
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.922
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         79.508
_diffrn_reflns_theta_min         2.939
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'PhotonJet (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    11.741
_exptl_absorpt_correction_T_max  0.666
_exptl_absorpt_correction_T_min  0.382
_exptl_absorpt_correction_type   gaussian
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.43.108a (Rigaku Oxford Diffraction, 2024)
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            'clear light orange'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_modifier   light
_exptl_crystal_colour_primary    orange
_exptl_crystal_density_diffrn    1.491
_exptl_crystal_description       plate
_exptl_crystal_F_000             920
_exptl_crystal_recrystallization_method
'Re-crystallisation from solvent: Hexane/CH2Cl2'
_exptl_crystal_size_max          0.18
_exptl_crystal_size_mid          0.08
_exptl_crystal_size_min          0.07
_refine_diff_density_max         0.302
_refine_diff_density_min         -0.414
_refine_diff_density_rms         0.056
_refine_ls_abs_structure_details
;
 Flack x determined using 1557 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.014(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.064
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     255
_refine_ls_number_reflns         3968
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.064
_refine_ls_R_factor_all          0.0307
_refine_ls_R_factor_gt           0.0293
_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^)+(0.0425P)^2^+0.7938P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0744
_refine_ls_wR_factor_ref         0.0750
_reflns_Friedel_coverage         0.783
_reflns_Friedel_fraction_full    0.998
_reflns_Friedel_fraction_max     0.884
_reflns_number_gt                3815
_reflns_number_total             3968
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d6cc00435k2.cif
_cod_data_source_block           exp_95_autored
_cod_depositor_comments
'Adding full bibliography for 7135696--7135704.cif.'
_cod_database_code               7135702
_shelx_shelxl_version_number     2018/3
_chemical_oxdiff_formula         C26H22Fe2
_shelx_estimated_absorpt_t_max   0.494
_shelx_estimated_absorpt_t_min   0.226
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Aromatic/amide H refined with riding coordinates:
 C007(H007), C008(H008), C00A(H00A), C00B(H00B), C00E(H00E), C00G(H00G),
 C00H(H00H), C00I(H00I), C00J(H00J), C00L(H00L), C00M(H00M), C00N(H00N),
 C00O(H00O), C00Q(H00R), C00R(H00S), C00S(H00T)
2.b Idealised Me refined as rotating group:
 C00K(H00C,H00D,H00F), C00P(H00K,H00P,H00Q)
;
_shelx_res_checksum              3208
_olex2_submission_special_instructions 'No special instructions were received'
_oxdiff_exptl_absorpt_empirical_details
;
Empirical correction (ABSPACK) includes:
- Absorption correction using spherical harmonics
- Frame scaling
;
_oxdiff_exptl_absorpt_empirical_full_max 1.218
_oxdiff_exptl_absorpt_empirical_full_min 0.878