The unexpected racemization and hydrogen-deuterium exchange of the hydrogen at the α-carbon of proline analogs containing the 5-azoniaspiro[4.4]nonyl-group.
Setner, B.; Wierzbicka, M.; Jerzykiewicz, L.; Lisowski, M.; Szewczuk, Z.; Organic & biomolecular chemistry 16 (2018) 825–831; doi:10.1039/c7ob02926h

data_7156055
_publ_section_title
;
 The unexpected racemization and hydrogen-deuterium exchange of the
 hydrogen at the \a-carbon of proline analogs containing the
 5-azoniaspiro[4.4]nonyl-group.
;
_journal_issue                   5
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              825
_journal_page_last               831
_journal_paper_doi               10.1039/c7ob02926h
_journal_volume                  16
_journal_year                    2018
_chemical_absolute_configuration rm
_chemical_formula_sum            'C43 H47 B N2 O3'
_chemical_formula_weight         650.63
_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   mixed
_audit_creation_method           SHELXL-2016/4
_audit_update_record
;
2017-10-05 deposited with the CCDC.
2018-01-05 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   9.6421(8)
_cell_length_b                   18.6118(12)
_cell_length_c                   20.0924(14)
_cell_measurement_reflns_used    3153
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      36.93
_cell_measurement_theta_min      3.012
_cell_volume                     3605.7(5)
_computing_cell_refinement       'CrysAlisPro 1.171.38.43 (Rigaku OD, 2015)'
_computing_data_collection       'CrysAlisPro 1.171.38.43 (Rigaku OD, 2015)'
_computing_data_reduction        'CrysAlisPro 1.171.38.43 (Rigaku OD, 2015)'
_computing_molecular_graphics    'DIAMOND (Brandenburg, 2006)'
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_computing_structure_solution    'SHELXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_detector_area_resol_mean 8.3359
_diffrn_measured_fraction_theta_full 0.987
_diffrn_measured_fraction_theta_max 0.986
_diffrn_measurement_device_type  'Xcalibur, Sapphire2, large Be window'
_diffrn_measurement_method       'omega and phi'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0262
_diffrn_reflns_av_unetI/netI     0.0750
_diffrn_reflns_Laue_measured_fraction_full 0.987
_diffrn_reflns_Laue_measured_fraction_max 0.986
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       22
_diffrn_reflns_limit_k_min       -10
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_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            8296
_diffrn_reflns_point_group_measured_fraction_full 0.911
_diffrn_reflns_point_group_measured_fraction_max 0.903
_diffrn_reflns_theta_full        25.000
_diffrn_reflns_theta_max         25.685
_diffrn_reflns_theta_min         2.984
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.074
_exptl_crystal_colour            colorless
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_exptl_crystal_size_max          0.212
_exptl_crystal_size_mid          0.184
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_refine_diff_density_min         -0.214
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_refine_ls_abs_structure_details
;
 Flack x determined using 1612 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.1(10)
_refine_ls_extinction_method     none
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_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
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_refine_ls_number_reflns         6191
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.034
_refine_ls_R_factor_all          0.0697
_refine_ls_R_factor_gt           0.0490
_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^)+(0.0345P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0883
_refine_ls_wR_factor_ref         0.0970
_reflns_Friedel_coverage         0.630
_reflns_Friedel_fraction_full    0.812
_reflns_Friedel_fraction_max     0.796
_reflns_number_gt                5011
_reflns_number_total             6191
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c7ob02926h2.cif
_cod_data_source_block           zs01
_cod_depositor_comments          'Adding full bibliography for 7156055.cif.'
_cod_database_code               7156055
_shelx_shelxl_version_number     2016/4
_shelx_res_checksum              78144