A surprising steric effect on a tandem cycloaddition/ring-opening reaction: rapid syntheses of difluorinated analogues of (hydroxymethyl)conduritols.
Fawcett, John; Moralee, Andrew C; Percy, Jonathan M; Salafia, Vittoria; Vincent, Mark A; Hillier, Ian H; Chemical communications (Cambridge, England)  (2004) 1062–1063; doi:10.1039/b401245c

data_7102620
_publ_section_title
;
 A surprising steric effect on a tandem cycloaddition/ring-opening
 reaction: rapid syntheses of difluorinated analogues of
 (hydroxymethyl)conduritols.
;
_journal_issue                   9
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              1062
_journal_page_last               1063
_journal_paper_doi               10.1039/b401245c
_journal_year                    2004
_chemical_formula_sum            'C14 H18 Br F2 N O5'
_chemical_formula_weight         398.20
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_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                 102.7150(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.6660(9)
_cell_length_b                   8.0535(6)
_cell_length_c                   18.3629(14)
_cell_measurement_reflns_used    4659
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      27.70
_cell_measurement_theta_min      2.27
_cell_volume                     1682.9(2)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega 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  0.0269
_diffrn_reflns_av_sigmaI/netI    0.0303
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            12743
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         26.00
_diffrn_reflns_theta_min         1.79
_exptl_absorpt_coefficient_mu    2.486
_exptl_absorpt_correction_T_max  0.801
_exptl_absorpt_correction_T_min  0.676
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details
;
absorption correction based on 7337 reflections (SADABS); Rint 0.054 before
correction and 0.026 after.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.572
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             808
_exptl_crystal_size_max          0.29
_exptl_crystal_size_mid          0.19
_exptl_crystal_size_min          0.13
_refine_diff_density_max         0.536
_refine_diff_density_min         -0.348
_refine_diff_density_rms         0.064
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.993
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     212
_refine_ls_number_reflns         3310
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.993
_refine_ls_R_factor_all          0.0417
_refine_ls_R_factor_gt           0.0338
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0571P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0888
_refine_ls_wR_factor_ref         0.0914
_reflns_number_gt                2699
_reflns_number_total             3310
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b401245c_cif.txt
_cod_data_source_block           8
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to '/home/saulius/struct/CIF-dictionaries/cif_core.dic'
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_enum 1527 2010-12-29 10:47:43Z saulius 
;
_cod_original_sg_symbol_H-M      P2(1)/c
_cod_database_code               7102620