Enantioselective Synthesis of α,α-Disubstituted Cyclopentenes by an N-Heterocyclic Carbene-Catalyzed Desymmetrization of 1,3-Diketones
Manabu Wadamoto; Eric M. Phillips; Troy E. Reynolds; Karl A. Scheidt; Journal of the American Chemical Society 129 (2007) 10098–10099; doi:10.1021/ja073987e

data_4109803
_publ_section_title
;
 Enantioselective Synthesis of \a,\a-Disubstituted Cyclopentenes by an
 N-Heterocyclic Carbene-Catalyzed Desymmetrization of 1,3-Diketones
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              10098
_journal_page_last               10099
_journal_paper_doi               10.1021/ja073987e
_journal_volume                  129
_journal_year                    2007
_chemical_formula_moiety         'C26 H24 Br N O2'
_chemical_formula_sum            'C26 H24 Br N O2'
_chemical_formula_weight         462.36
_chemical_name_common            'Cyclopentene Absolute Structure'
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 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                 92.9710(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.2308(5)
_cell_length_b                   23.0250(13)
_cell_length_c                   10.6007(6)
_cell_measurement_reflns_used    7183
_cell_measurement_temperature    153(2)
_cell_measurement_theta_max      28.82
_cell_measurement_theta_min      2.83
_cell_volume                     2250.0(2)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SMART'
_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      153(2)
_diffrn_measured_fraction_theta_full 0.925
_diffrn_measured_fraction_theta_max 0.925
_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  0.0398
_diffrn_reflns_av_sigmaI/netI    0.0409
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       31
_diffrn_reflns_limit_k_min       -31
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            21120
_diffrn_reflns_theta_full        28.85
_diffrn_reflns_theta_max         28.85
_diffrn_reflns_theta_min         1.77
_exptl_absorpt_coefficient_mu    1.850
_exptl_absorpt_correction_T_max  0.7219
_exptl_absorpt_correction_T_min  0.4767
_exptl_absorpt_correction_type   analytical
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.392
_exptl_crystal_description       columnar
_exptl_crystal_F_000             988
_exptl_crystal_size_max          0.59
_exptl_crystal_size_mid          0.27
_exptl_crystal_size_min          0.18
_refine_diff_density_max         0.796
_refine_diff_density_min         -0.232
_refine_diff_density_rms         0.058
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.010(4)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.836
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     549
_refine_ls_number_reflns         10633
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.836
_refine_ls_R_factor_all          0.0356
_refine_ls_R_factor_gt           0.0305
_refine_ls_shift/su_max          2.784
_refine_ls_shift/su_mean         0.018
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0644P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0772
_refine_ls_wR_factor_ref         0.0798
_reflns_number_gt                9531
_reflns_number_total             10633
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja073987esi20070615_113922.cif
_cod_data_source_block           x
_cod_database_code               4109803