Controlled beta-protonation and [4+2] cycloaddition of enals and chalcones via N-heterocyclic carbene/acid catalysis: toward substrate independent reaction control
Zhenqian Fu; Hui Sun; Shaojin Chen; Bhoopendra Tiwari; Guohui Li; Yonggui Robin Chi; Chem.Commun. 49 (2013) 261–; doi:10.1039/c2cc36564b

data_7108727
_publ_section_title
;
 Controlled beta-protonation and [4+2] cycloaddition of enals and
 chalcones via N-heterocyclic carbene/acid catalysis: toward substrate
 independent reaction control
;
_journal_name_full               Chem.Commun.
_journal_page_first              261
_journal_paper_doi               10.1039/c2cc36564b
_journal_volume                  49
_journal_year                    2013
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C24 H19 Br O2'
_chemical_formula_sum            'C24 H19 Br O2'
_chemical_formula_weight         419.30
_space_group_IT_number           19
_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
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   5.7877(6)
_cell_length_b                   15.8468(17)
_cell_length_c                   20.507(2)
_cell_measurement_reflns_used    1555
_cell_measurement_temperature    103(2)
_cell_measurement_theta_max      22.24
_cell_measurement_theta_min      3.25
_cell_volume                     1880.8(3)
_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 0.983
_diffrn_measured_fraction_theta_max 0.983
_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  0.0522
_diffrn_reflns_av_sigmaI/netI    0.0989
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -4
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -20
_diffrn_reflns_limit_l_max       25
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            8357
_diffrn_reflns_theta_full        26.99
_diffrn_reflns_theta_max         26.99
_diffrn_reflns_theta_min         1.62
_exptl_absorpt_coefficient_mu    2.202
_exptl_absorpt_correction_T_max  0.8099
_exptl_absorpt_correction_T_min  0.4729
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.481
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             856
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.483
_refine_diff_density_min         -0.643
_refine_diff_density_rms         0.137
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.014(17)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.075
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     244
_refine_ls_number_reflns         4012
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.075
_refine_ls_R_factor_all          0.0700
_refine_ls_R_factor_gt           0.0479
_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^)+(0.0646P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1028
_refine_ls_wR_factor_ref         0.1430
_reflns_number_gt                3186
_reflns_number_total             4012
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c2cc36564b.txt
_cod_data_source_block           cyg51
_cod_original_cell_volume        1880.9(3)
_cod_original_sg_symbol_H-M      P2(1)2(1)2(1)
_cod_database_code               7108727