Formal Diels-Alder reactions of chalcones and formylcyclopropanes catalyzed by chiral N-heterocyclic carbenes.
Lv, Hui; Mo, Junming; Fang, Xinqiang; Chi, Yonggui Robin; Organic letters 13 (2011) 5366–5369; doi:10.1021/ol202250s

data_1502504
_publ_section_title
;
 Formal Diels-Alder reactions of chalcones and formylcyclopropanes
 catalyzed by chiral N-heterocyclic carbenes.
;
_journal_issue                   19
_journal_name_full               'Organic letters'
_journal_page_first              5366
_journal_page_last               5369
_journal_paper_doi               10.1021/ol202250s
_journal_volume                  13
_journal_year                    2011
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C26 H20 Br2 O3'
_chemical_formula_sum            'C26 H20 Br2 O3'
_chemical_formula_weight         540.24
_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                 100.4500(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   15.3997(5)
_cell_length_b                   6.0444(3)
_cell_length_c                   23.8606(10)
_cell_measurement_reflns_used    5760
_cell_measurement_temperature    103(2)
_cell_measurement_theta_max      29.70
_cell_measurement_theta_min      2.60
_cell_volume                     2184.15(16)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      103(2)
_diffrn_measured_fraction_theta_full 0.993
_diffrn_measured_fraction_theta_max 0.993
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w 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  0.0315
_diffrn_reflns_av_sigmaI/netI    0.0564
_diffrn_reflns_limit_h_max       21
_diffrn_reflns_limit_h_min       -21
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       33
_diffrn_reflns_limit_l_min       -33
_diffrn_reflns_number            34132
_diffrn_reflns_theta_full        30.07
_diffrn_reflns_theta_max         30.07
_diffrn_reflns_theta_min         2.38
_exptl_absorpt_coefficient_mu    3.738
_exptl_absorpt_correction_T_max  0.4674
_exptl_absorpt_correction_T_min  0.3163
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.643
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1080
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.24
_refine_diff_density_max         0.632
_refine_diff_density_min         -0.539
_refine_diff_density_rms         0.090
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.003(5)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.022
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     559
_refine_ls_number_reflns         11423
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.022
_refine_ls_R_factor_all          0.0426
_refine_ls_R_factor_gt           0.0316
_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^)+(0.0166P)^2^+0.7601P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0604
_refine_ls_wR_factor_ref         0.0638
_reflns_number_gt                10011
_reflns_number_total             11423
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol202250s_si_003.cif
_cod_data_source_block           cyg12s
_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_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_sg_symbol_H-M      P2(1)
_cod_database_code               1502504