N-Heterocyclic carbene-catalyzed highly enantioselective synthesis of substituted dihydropyranopyrazolones.
Zhang, Han-Ming; Lv, Hui; Ye, Song; Organic & biomolecular chemistry 11 (2013) 6255–6257; doi:10.1039/c3ob41455h

data_7153080
_publ_section_title
;
 N-Heterocyclic carbene-catalyzed highly enantioselective synthesis of
 substituted dihydropyranopyrazolones.
;
_journal_issue                   37
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              6255
_journal_page_last               6257
_journal_paper_doi               10.1039/c3ob41455h
_journal_volume                  11
_journal_year                    2013
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C26 H21 Br N2 O2'
_chemical_formula_sum            'C26 H21 Br N2 O2'
_chemical_formula_weight         473.36
_space_group_IT_number           152
_symmetry_cell_setting           trigonal
_symmetry_space_group_name_Hall  'P 31 2"'
_symmetry_space_group_name_H-M   'P 31 2 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                 90.00
_cell_angle_gamma                120.00
_cell_formula_units_Z            6
_cell_length_a                   9.7691(4)
_cell_length_b                   9.7691(4)
_cell_length_c                   39.742(3)
_cell_measurement_reflns_used    9278
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      26.36
_cell_measurement_theta_min      1.54
_cell_volume                     3284.7(3)
_computing_cell_refinement       'CrystalClear (Rigaku Inc., 2007)'
_computing_data_collection       'CrystalClear (Rigaku Inc., 2007)'
_computing_data_reduction        'CrystalClear (Rigaku Inc., 2007)'
_computing_molecular_graphics    'Olex2 ver 1.1'
_computing_publication_material  'SHELX97 (Sheldrick, 2008)'
_computing_structure_refinement  'Olex2 ver 1.1'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.989
_diffrn_measured_fraction_theta_max 0.989
_diffrn_measurement_device_type  'Saturn724+ CCD'
_diffrn_measurement_method       '\w scans at fixed \c = 45\%'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0491
_diffrn_reflns_av_sigmaI/netI    0.0314
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       48
_diffrn_reflns_limit_l_min       -49
_diffrn_reflns_number            22218
_diffrn_reflns_theta_full        26.36
_diffrn_reflns_theta_max         26.36
_diffrn_reflns_theta_min         2.62
_exptl_absorpt_coefficient_mu    1.903
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.7036
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'CrystalClear (Rigaku Inc., 2007)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.436
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1452
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.28
_exptl_crystal_size_min          0.21
_refine_diff_density_max         0.257
_refine_diff_density_min         -0.253
_refine_diff_density_rms         0.048
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.006(8)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.150
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     281
_refine_ls_number_reflns         4425
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.150
_refine_ls_R_factor_all          0.0426
_refine_ls_R_factor_gt           0.0393
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0335P)^2^+0.9047P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0856
_refine_ls_wR_factor_ref         0.0872
_reflns_number_gt                4196
_reflns_number_total             4425
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c3ob41455h.txt
_cod_data_source_block           sa2745
_cod_original_sg_symbol_H-M      P3(1)2(1)
_cod_database_code               7153080