Robust trans-Amide Helical Structure of Oligomers of Bicyclic Mimics of β-Proline: Impact of Positional Switching of Bridgehead Substituent on Amide cis-trans Equilibrium.
Wang, Siyuan; Otani, Yuko; Liu, Xin; Kawahata, Masatoshi; Yamaguchi, Kentaro; Ohwada, Tomohiko; The Journal of organic chemistry 79 (2014) 5287–5300; doi:10.1021/jo500916j

data_4029451
_publ_section_title
;
 Robust trans-Amide Helical Structure of Oligomers of Bicyclic Mimics of
 \b-Proline: Impact of Positional Switching of Bridgehead Substituent on
 Amide cis-trans Equilibrium.
;
_journal_issue                   11
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              5287
_journal_page_last               5300
_journal_paper_doi               10.1021/jo500916j
_journal_volume                  79
_journal_year                    2014
_chemical_absolute_configuration unk
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_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 110.277(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   7.321(6)
_cell_length_b                   11.808(9)
_cell_length_c                   9.419(8)
_cell_measurement_reflns_used    2483
_cell_measurement_temperature    120
_cell_measurement_theta_max      22.72
_cell_measurement_theta_min      2.31
_cell_volume                     763.8(11)
_computing_cell_refinement       SMART
_computing_data_collection       SMART
_computing_data_reduction        SAINT
_computing_molecular_graphics    'ORTEP-3 for Windows'
_computing_publication_material  SHELXL-97
_computing_structure_refinement  SHELXL-97
_computing_structure_solution    SHELXS-97
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_diffrn_detector_area_resol_mean 8.333
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.988
_diffrn_measurement_device_type  'Bruker SMART 1000 CCD area detector'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0490
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_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
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_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         27.59
_diffrn_reflns_theta_min         2.30
_diffrn_standards_decay_%        0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.094
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.241
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             308
_exptl_crystal_size_max          0.28
_exptl_crystal_size_mid          0.26
_exptl_crystal_size_min          0.05
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_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.2(8)
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_refine_ls_number_reflns         3479
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_refine_ls_restrained_S_all      0.951
_refine_ls_R_factor_all          0.0509
_refine_ls_R_factor_gt           0.0371
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0339P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0765
_refine_ls_wR_factor_ref         0.0803
_reflns_number_gt                2747
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_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo500916j_si_001.cif
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_cod_depositor_comments
'Adding full bibliography for 4029450--4029455.cif.'
_cod_original_sg_symbol_H-M      P21
_cod_database_code               4029451