Synthesis of Furo[3,2-c]benzopyrans via an Intramolecular [4 + 2] Cycloaddition Reaction of o-Quinonemethides.
Zhao, Li-Ming; Zhang, Ai-Li; Gao, Hua-Shuai; Zhang, Jie-Huan; The Journal of organic chemistry 80 (2015) 10353–10358; doi:10.1021/acs.joc.5b01641

data_4036343
_publ_section_title
;
 Synthesis of Furo[3,2-c]benzopyrans via an Intramolecular [4 + 2]
 Cycloaddition Reaction of o-Quinonemethides.
;
_journal_issue                   20
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              10353
_journal_page_last               10358
_journal_paper_doi               10.1021/acs.joc.5b01641
_journal_volume                  80
_journal_year                    2015
_chemical_absolute_configuration unk
_chemical_formula_sum            'C20 H20 O2'
_chemical_formula_weight         292.36
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_atom_sites_solution_hydrogens   mixed
_audit_creation_method           SHELXL-2014
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   8.033(2)
_cell_length_b                   10.739(3)
_cell_length_c                   18.778(5)
_cell_measurement_reflns_used    7457
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      27.05
_cell_measurement_theta_min      2.18
_cell_volume                     1619.9(7)
_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-2014 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-97 (Sheldrick 2008)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.949
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0206
_diffrn_reflns_av_unetI/netI     0.0174
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.949
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            12473
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.923
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.192
_diffrn_reflns_theta_min         2.758
_exptl_absorpt_coefficient_mu    0.076
_exptl_absorpt_correction_type   'none''SHELXS-97 (Sheldrick 2008)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.199
_exptl_crystal_description       block
_exptl_crystal_F_000             624
_exptl_crystal_size_max          0.15
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.124
_refine_diff_density_min         -0.198
_refine_diff_density_rms         0.047
_refine_ls_abs_structure_details
;
 Flack x determined using 1229 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.3(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.057
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     276
_refine_ls_number_reflns         3332
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.057
_refine_ls_R_factor_all          0.0383
_refine_ls_R_factor_gt           0.0350
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0507P)^2^+0.1328P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0842
_refine_ls_wR_factor_ref         0.0873
_reflns_Friedel_coverage         0.690
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.888
_reflns_number_gt                3104
_reflns_number_total             3332
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo5b01641_si_002.cif
_cod_data_source_block
C:\Users\yanli\Desktop\1-ZLM1~1\ZLM141105_ZAL_0m
_cod_original_cell_volume        1619.8(8)
_cod_database_code               4036343
_shelxl_version_number           2014-3
_shelx_res_checksum              53294
_shelx_hkl_checksum              42187