Synthesis and Conformational Properties of 3,4-Difluoro-l-prolines.
Hofman, Gert-Jan; Ottoy, Emile; Light, Mark E.; Kieffer, Bruno; Martins, Jose C.; Kuprov, Ilya; Sinnaeve, Davy; Linclau, Bruno; The Journal of organic chemistry 84 (2019) 3100–3120; doi:10.1021/acs.joc.8b02920

data_4033903
_publ_section_title
;
 Synthesis and Conformational Properties of 3,4-Difluoro-l-prolines.
;
_journal_issue                   6
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              3100
_journal_page_last               3120
_journal_paper_doi               10.1021/acs.joc.8b02920
_journal_volume                  84
_journal_year                    2019
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C8 H11 F2 N O3'
_chemical_formula_sum            'C8 H11 F2 N O3'
_chemical_formula_weight         207.18
_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'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2018-02-03
_audit_creation_method
;
Olex2 1.2-alpha
(compiled 2018.02.02 svn.r3481 for OlexSys, GUI svn.r5465)
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   6.92180(10)
_cell_length_b                   10.19260(10)
_cell_length_c                   13.0782(2)
_cell_measurement_reflns_used    3610
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      30.0230
_cell_measurement_theta_min      3.5450
_cell_volume                     922.68(2)
_computing_cell_refinement       'CrysAlisPro 1.171.39.9g (Rigaku OD, 2015)'
_computing_data_collection       'CrysAlisPro 1.171.39.9g (Rigaku OD, 2015)'
_computing_data_reduction        'CrysAlisPro 1.171.39.9g (Rigaku OD, 2015)'
_computing_molecular_graphics    'Olex2 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'ShelXL (Sheldrick, 2015)'
_computing_structure_solution    'ShelXT (Sheldrick, 2015)'
_diffrn_ambient_temperature      100(2)
_diffrn_detector                 'Hybrid Photon Counting'
_diffrn_detector_area_resol_mean 28.5714
_diffrn_detector_type            'Rigaku HG Saturn724+ (2x2 bin mode)'
_diffrn_measured_fraction_theta_full 0.996
_diffrn_measured_fraction_theta_max 0.997
_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    -36.00  14.00   1.00    1.00    --  -19.10 -57.00  60.00   50
  2  \w    -49.00  68.00   1.00    1.00    --  -19.10  57.00-150.00  117
  3  \w    -62.00   7.00   1.00    1.00    --  -19.10 -19.00-120.00   69
;
_diffrn_measurement_device       'three-circle quarter \c goniometer'
_diffrn_measurement_device_type  'Rigaku AFC12 FRE-HF'
_diffrn_measurement_method       'profile data from \w-scans'
_diffrn_measurement_specimen_support 'MiTeGen MicroMesh'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      -0.0913092000
_diffrn_orient_matrix_UB_12      0.0118933000
_diffrn_orient_matrix_UB_13      0.0227423000
_diffrn_orient_matrix_UB_21      -0.0465333000
_diffrn_orient_matrix_UB_22      -0.0238810000
_diffrn_orient_matrix_UB_23      -0.0446110000
_diffrn_orient_matrix_UB_31      0.0002210000
_diffrn_orient_matrix_UB_32      -0.0642750000
_diffrn_orient_matrix_UB_33      0.0208172000
_diffrn_radiation_collimation    0.3
_diffrn_radiation_monochromator  'Confocal mirrors, Varimax'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0241
_diffrn_reflns_av_unetI/netI     0.0292
_diffrn_reflns_Laue_measured_fraction_full 0.996
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -5
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            5319
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.496
_diffrn_reflns_theta_min         3.115
_diffrn_source                   'Rotating-anode X-ray tube'
_diffrn_source_current           55.0
_diffrn_source_power             2.475
_diffrn_source_target            Mo
_diffrn_source_type              'Rigaku 007 HF'
_diffrn_source_voltage           45.0
_exptl_absorpt_coefficient_mu    0.138
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.53743
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.39.9g (Rigaku Oxford Diffraction, 2015)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            'clear colourless'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.491
_exptl_crystal_description       block
_exptl_crystal_F_000             432
_exptl_crystal_recrystallization_method
'The material was recrystallised from DCM by slow evaporation'
_exptl_crystal_size_max          0.388
_exptl_crystal_size_mid          0.239
_exptl_crystal_size_min          0.059
_refine_diff_density_max         0.240
_refine_diff_density_min         -0.181
_refine_diff_density_rms         0.040
_refine_ls_abs_structure_details
;
 Flack x determined using 876 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.0(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.056
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     129
_refine_ls_number_reflns         2330
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.056
_refine_ls_R_factor_all          0.0329
_refine_ls_R_factor_gt           0.0315
_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^)+(0.0418P)^2^+0.1591P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0814
_refine_ls_wR_factor_ref         0.0829
_reflns_Friedel_coverage         0.712
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     1.000
_reflns_number_gt                2234
_reflns_number_total             2330
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo8b02920_si_002.cif
_cod_data_source_block           2018sot0002_k1_100k
_cod_database_code               4033903
_shelx_shelxl_version_number     2016/6
_chemical_oxdiff_formula         C8H11F2NO
_chemical_oxdiff_usercomment     GJH-8254-85
_diffrn_measurement_device_type2 'Rigaku AFC12 (Right)'
_reflns_odcompleteness_completeness 93.10
_reflns_odcompleteness_iscentric 1
_reflns_odcompleteness_theta     30.44
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Ternary CH refined with riding coordinates:
 C4(H4), C5(H5), C6(H6)
2.b Secondary CH2 refined with riding coordinates:
 C3(H3A,H3B)
2.c Idealised Me refined as rotating group:
 C1(H1A,H1B,H1C), C8(H8A,H8B,H8C)
;
_shelx_res_checksum              44667
_shelx_hkl_checksum              11558
_olex2_date_sample_submission    2018-01-01
_olex2_diffrn_ambient_temperature_device 'Oxford Cryosystems'
_olex2_exptl_crystal_mounting_method
'The crystal was mounted on a MITIGEN holder with silicon oil'
_olex2_submission_original_sample_id GJH-8254-85
_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 1.541
_oxdiff_exptl_absorpt_empirical_full_min 0.673