Strain-release driven spirocyclization of bicyclo[1.1.0]butanes: access to 6,7-diazaspiro[3.4]octanes
Jiang, Qin; Dong, Jianyang; Lei, Fang; Yu, Dejiang; Li, Ting; Sun, Huaming; Xue, Dong; Chemical Science 16 (2025) 12189–12195; doi:10.1039/D5SC03141A

data_1574818
_publ_section_title
;
 Strain-release driven spirocyclization of bicyclo[1.1.0]butanes: access
 to 6,7-diazaspiro[3.4]octanes
;
_journal_issue                   26
_journal_name_full               'Chemical Science'
_journal_page_first              12189
_journal_page_last               12195
_journal_paper_doi               10.1039/D5SC03141A
_journal_volume                  16
_journal_year                    2025
_chemical_formula_moiety         'C27 H22 N2 O2'
_chemical_formula_sum            'C27 H22 N2 O2'
_chemical_formula_weight         406.46
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2025-02-27
_audit_creation_method
;
Olex2 1.5
(compiled 2024.02.16 svn.r378c4104 for OlexSys, GUI svn.r6928)
;
_audit_update_record
;
2025-02-27 deposited with the CCDC.	2025-06-04 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 100.439(3)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   15.0680(11)
_cell_length_b                   6.3158(5)
_cell_length_c                   22.0503(16)
_cell_measurement_reflns_used    9970
_cell_measurement_temperature    200.00
_cell_measurement_theta_max      68.057
_cell_measurement_theta_min      4.077
_cell_volume                     2063.7(3)
_computing_cell_refinement       'SAINT V8.40A (Bruker, 2019)'
_computing_data_reduction        'SAINT V8.40A (Bruker, 2019)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2019/2 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_temperature      200.00
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0827
_diffrn_reflns_av_unetI/netI     0.0546
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.996
_diffrn_reflns_limit_h_max       18
_diffrn_reflns_limit_h_min       -18
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       26
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            29808
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.996
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         68.290
_diffrn_reflns_theta_min         4.077
_diffrn_source_current           50.0
_diffrn_source_power             2.5
_diffrn_source_voltage           50.0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.658
_exptl_absorpt_correction_T_max  0.7531
_exptl_absorpt_correction_T_min  0.5666
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1341 before and 0.0857 after correction.
The Ratio of minimum to maximum transmission is 0.7524.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            'clear light colourless'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_modifier   light
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.308
_exptl_crystal_description       block
_exptl_crystal_F_000             856
_exptl_crystal_size_max          0.3
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.1
_refine_diff_density_max         0.245
_refine_diff_density_min         -0.248
_refine_diff_density_rms         0.044
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.093
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     280
_refine_ls_number_reflns         3783
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.093
_refine_ls_R_factor_all          0.0824
_refine_ls_R_factor_gt           0.0574
_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^)+(0.0597P)^2^+1.2765P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1540
_refine_ls_wR_factor_ref         0.1616
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2935
_reflns_number_total             3783
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc03141a2.cif
_cod_data_source_block           s
_cod_depositor_comments          'Adding full bibliography for 1574818.cif.'
_cod_database_code               1574818
_shelx_shelxl_version_number     2019/2
_shelx_estimated_absorpt_t_max   0.937
_shelx_estimated_absorpt_t_min   0.827
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
2.a Ternary CH refined with riding coordinates:
 C1(H1)
2.b Secondary CH2 refined with riding coordinates:
 C16(H16A,H16B), C22(H22A,H22B), C26(H26A,H26B)
2.c Aromatic/amide H refined with riding coordinates:
 C12(H12), C27(H27), C7(H7), C15(H15), C2(H2), C17(H17), C9(H9), C19(H19),
 C5(H5), C21(H21), C11(H11), C23(H23), C3(H3), C25(H25), C13(H13)
;
_shelx_res_checksum              15277
_olex2_submission_special_instructions 'No special instructions were received'