Diastereoselective synthesis and conformational analysis of 4,5-difluoropipecolic acids.
Chen, Suo; Ruan, Yao; Lu, Ji-Liang; Hunter, Luke; Hu, Xiang-Guo; Organic & biomolecular chemistry 18 (2020) 8192–8198; doi:10.1039/d0ob01811b

data_7157726
_publ_section_title
;
 Diastereoselective synthesis and conformational analysis of
 4,5-difluoropipecolic acids.
;
_journal_issue                   40
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              8192
_journal_page_last               8198
_journal_paper_doi               10.1039/d0ob01811b
_journal_volume                  18
_journal_year                    2020
_chemical_absolute_configuration s
_chemical_formula_moiety         C17H23F2NO3
_chemical_formula_sum            'C17 H23 F2 N O3'
_chemical_formula_weight         327.36
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2020-08-20 deposited with the CCDC.	2020-09-28 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 98.790(4)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   9.0751(5)
_cell_length_b                   6.1933(3)
_cell_length_c                   15.1581(7)
_cell_measurement_reflns_used    4471
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      26.5570
_cell_measurement_theta_min      3.9720
_cell_volume                     841.95(7)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.996
_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           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0304
_diffrn_reflns_av_unetI/netI     0.0321
_diffrn_reflns_Laue_measured_fraction_full 0.996
_diffrn_reflns_Laue_measured_fraction_max 0.996
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            8892
_diffrn_reflns_point_group_measured_fraction_full 0.968
_diffrn_reflns_point_group_measured_fraction_max 0.966
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.496
_diffrn_reflns_theta_min         3.266
_exptl_absorpt_coefficient_mu    0.102
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.291
_exptl_crystal_description       block
_exptl_crystal_F_000             348
_exptl_crystal_size_max          0.140
_exptl_crystal_size_mid          0.120
_exptl_crystal_size_min          0.080
_exptl_transmission_factor_max   1.0000
_exptl_transmission_factor_min   0.7516
_refine_diff_density_max         0.138
_refine_diff_density_min         -0.196
_refine_diff_density_rms         0.044
_refine_ls_abs_structure_details
; 
 Flack x determined using 1051 quotients [(I+)-(I-)]/[(I+)+(I-)] 
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259). 
;
_refine_ls_abs_structure_Flack   0.3(4)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.099
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     212
_refine_ls_number_reflns         3025
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.098
_refine_ls_R_factor_all          0.0435
_refine_ls_R_factor_gt           0.0392
_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^)+(0.0490P)^2^+0.0236P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0916
_refine_ls_wR_factor_ref         0.0950
_reflns_Friedel_coverage         0.766
_reflns_Friedel_fraction_full    0.933
_reflns_Friedel_fraction_max     0.930
_reflns_number_gt                2760
_reflns_number_total             3025
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d0ob01811b2.cif
_cod_data_source_block           A
_cod_depositor_comments
'Adding full bibliography for 7157725--7157727.cif.'
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               7157726
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.986
_shelx_estimated_absorpt_t_max   0.992
_shelx_res_checksum              11414
_shelx_hkl_checksum              26430