Acid Catalyzed Ring Transformation of Benzofurans to Tri- and Tetrasubstituted Furans
Seema Dhiman; S. S. V. Ramasastry; Journal of Organic Chemistry 78 (2013) 10427–10436; doi:10.1021/jo4018233

data_4028686
_publ_section_title
;
 Acid Catalyzed Ring Transformation of Benzofurans to Tri- and
 Tetrasubstituted Furans
;
_journal_name_full               'Journal of Organic Chemistry'
_journal_page_first              10427
_journal_page_last               10436
_journal_paper_doi               10.1021/jo4018233
_journal_volume                  78
_journal_year                    2013
_chemical_formula_moiety         'C18 H22 O3'
_chemical_formula_sum            'C18 H22 O3'
_chemical_formula_weight         286.36
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_cell_angle_alpha                90
_cell_angle_beta                 99.065(4)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   10.9516(7)
_cell_length_b                   7.0293(4)
_cell_length_c                   21.4714(13)
_cell_measurement_reflns_used    1079
_cell_measurement_temperature    150.(2)
_cell_measurement_theta_max      20.1697
_cell_measurement_theta_min      2.2442
_cell_volume                     1632.27(17)
_computing_cell_refinement       'SAINT V7.68A (Bruker AXS, 2009)'
_computing_data_collection       'APEX2 (Bruker)'
_computing_data_reduction        'SAINT V7.68A (Bruker AXS, 2009)'
_computing_molecular_graphics    'SHELXTL (Bruker AXS)'
_computing_publication_material  'SHELXTL (Bruker AXS)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      150.(2)
_diffrn_detector_area_resol_mean 8.3333
_diffrn_measured_fraction_theta_full 0.992
_diffrn_measured_fraction_theta_max 0.992
_diffrn_measurement_device_type  'Bruker Kappa APEX II'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0584
_diffrn_reflns_av_sigmaI/netI    0.0788
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            7874
_diffrn_reflns_theta_full        23.35
_diffrn_reflns_theta_max         23.35
_diffrn_reflns_theta_min         1.92
_diffrn_source                   'fine focus'
_diffrn_source_type              'sealed tube'
_exptl_absorpt_coefficient_mu    0.078
_exptl_absorpt_correction_T_max  0.7449
_exptl_absorpt_correction_T_min  0.5813
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS V2008/1 (Bruker AXS)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.165
_exptl_crystal_description       'rod shaped'
_exptl_crystal_F_000             616
_exptl_crystal_size_max          0.200
_exptl_crystal_size_mid          0.100
_exptl_crystal_size_min          0.080
_refine_diff_density_max         0.471
_refine_diff_density_min         -0.244
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.031
_refine_ls_hydrogen_treatment    undef
_refine_ls_matrix_type           full
_refine_ls_number_parameters     195
_refine_ls_number_reflns         2359
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.031
_refine_ls_R_factor_all          0.1336
_refine_ls_R_factor_gt           0.0799
_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^)+(0.1206P)^2^+1.2929P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2048
_refine_ls_wR_factor_ref         0.2358
_reflns_number_gt                1423
_reflns_number_total             2359
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo4018233_si_002_1.cif
_cod_data_source_block           2
_cod_database_code               4028686