Stereodivergency of triazolium and imidazolium-derived NHCs for catalytic, enantioselective cyclopentane synthesis.
Kaeobamrung, Juthanat; Bode, Jeffrey W.; Organic letters 11 (2009) 677–680; doi:10.1021/ol802739d

data_1503764
_publ_section_title
;
 Stereodivergency of triazolium and imidazolium-derived NHCs for
 catalytic, enantioselective cyclopentane synthesis.
;
_journal_issue                   3
_journal_name_full               'Organic letters'
_journal_page_first              677
_journal_page_last               680
_journal_paper_doi               10.1021/ol802739d
_journal_volume                  11
_journal_year                    2009
_chemical_absolute_configuration ad
_chemical_formula_sum            'C21 H21 Br O3'
_chemical_formula_weight         401.29
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_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
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_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
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_cell_length_b                   17.021(6)
_cell_length_c                   17.923(7)
_cell_measurement_temperature    273(2)
_cell_volume                     1863.4(12)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      273(2)
_diffrn_measured_fraction_theta_full 0.948
_diffrn_measured_fraction_theta_max 0.948
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'Omega scan'
_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  0.1665
_diffrn_reflns_av_sigmaI/netI    0.2659
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       19
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            10149
_diffrn_reflns_theta_full        25.51
_diffrn_reflns_theta_max         25.51
_diffrn_reflns_theta_min         1.65
_exptl_absorpt_coefficient_mu    2.222
_exptl_absorpt_correction_T_max  0.312
_exptl_absorpt_correction_T_min  0.183
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   'psi scan'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.431
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             824
_exptl_crystal_size_max          0.3
_exptl_crystal_size_mid          0.07
_exptl_crystal_size_min          0.07
_refine_diff_density_max         0.488
_refine_diff_density_min         -0.860
_refine_diff_density_rms         0.081
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.05(2)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.778
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     238
_refine_ls_number_reflns         3193
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.778
_refine_ls_R_factor_all          0.2082
_refine_ls_R_factor_gt           0.0568
_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^)+(0.0598P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1177
_refine_ls_wR_factor_ref         0.1550
_reflns_number_gt                1058
_reflns_number_total             3193
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol802739d_si_004.cif
_cod_data_source_block           br_3_7
_cod_original_cell_volume        1863.2(12)
_cod_original_sg_symbol_H-M      P2(1)2(1)2(1)
_cod_database_code               1503764