An unusual Me3SiI-promoted [4+2] annulation and reduction: an efficient approach to construct 4H-benzopyrans
Feijun Wang; Mingliang Qu; Feng Chen; Li Li; Min Shi; Chem.Commun. 48 (2012) 437–; doi:10.1039/c1cc16028a

data_7107165
_publ_section_title
;
 An unusual Me3SiI-promoted [4+2] annulation and reduction: an efficient
 approach to construct 4H-benzopyrans
;
_journal_name_full               Chem.Commun.
_journal_page_first              437
_journal_paper_doi               10.1039/c1cc16028a
_journal_volume                  48
_journal_year                    2012
_chemical_formula_sum            'C14 H13 Br O3'
_chemical_formula_weight         309.15
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 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                 92.902(8)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.081(4)
_cell_length_b                   20.421(9)
_cell_length_c                   6.813(3)
_cell_measurement_reflns_used    2266
_cell_measurement_temperature    133(2)
_cell_measurement_theta_max      29.07
_cell_measurement_theta_min      2.46
_cell_volume                     1261.8(10)
_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, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      133(2)
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_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  0.0000
_diffrn_reflns_av_sigmaI/netI    0.0519
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       0
_diffrn_reflns_limit_k_min       -24
_diffrn_reflns_limit_l_max       8
_diffrn_reflns_limit_l_min       -8
_diffrn_reflns_number            2207
_diffrn_reflns_theta_full        25.03
_diffrn_reflns_theta_max         25.03
_diffrn_reflns_theta_min         1.99
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    3.255
_exptl_absorpt_correction_T_max  0.5622
_exptl_absorpt_correction_T_min  0.4626
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   twinabs
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.627
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             624
_exptl_crystal_size_max          0.28
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.20
_refine_diff_density_max         2.091
_refine_diff_density_min         -1.318
_refine_diff_density_rms         0.140
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.105
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     165
_refine_ls_number_reflns         2207
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.105
_refine_ls_R_factor_all          0.0686
_refine_ls_R_factor_gt           0.0527
_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^)+(0.0850P)^2^+1.9706P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1484
_refine_ls_wR_factor_ref         0.1586
_reflns_number_gt                1802
_reflns_number_total             2207
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c1cc16028a.txt
_cod_data_source_block           dm11275
_cod_original_sg_symbol_H-M      P2(1)/c
_cod_database_code               7107165