N-heterocyclic carbene catalyzed annulation of benzofuran-2,3-diones and enals: a concise synthesis of spiro-bis-lactone.
Wang, Ze-Dong; Wang, Feng; Li, Xin; Cheng, Jin-Pei; Organic & biomolecular chemistry 11 (2013) 5634–5641; doi:10.1039/c3ob41028e

data_7153040
_publ_section_title
;
 N-heterocyclic carbene catalyzed annulation of benzofuran-2,3-diones and
 enals: a concise synthesis of spiro-bis-lactone.
;
_journal_issue                   34
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              5634
_journal_page_last               5641
_journal_paper_doi               10.1039/c3ob41028e
_journal_volume                  11
_journal_year                    2013
_chemical_formula_sum            'C20 H17 Cl O4'
_chemical_formula_weight         356.79
_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                 94.226(6)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.355(4)
_cell_length_b                   6.959(3)
_cell_length_c                   25.667(10)
_cell_measurement_reflns_used    4714
_cell_measurement_temperature    113(2)
_cell_measurement_theta_max      28.0
_cell_measurement_theta_min      1.6
_cell_volume                     1666.4(12)
_computing_cell_refinement       CrystalClear
_computing_data_collection       CrystalClear
_computing_data_reduction        CrystalClear
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'CrystalStructure 3.8'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      113(2)
_diffrn_detector_area_resol_mean 14.22
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_diffrn_measurement_device_type  'Rigaku Saturn724 CCD'
_diffrn_measurement_method       '\w and \f scans'
_diffrn_radiation_monochromator  multilayer
_diffrn_radiation_source         'rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0817
_diffrn_reflns_av_sigmaI/netI    0.0986
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       33
_diffrn_reflns_limit_l_min       -33
_diffrn_reflns_number            17936
_diffrn_reflns_theta_full        28.00
_diffrn_reflns_theta_max         28.00
_diffrn_reflns_theta_min         1.59
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.252
_exptl_absorpt_correction_T_max  0.9704
_exptl_absorpt_correction_T_min  0.9514
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   CrystalClear
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.422
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Prism
_exptl_crystal_F_000             744
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.12
_refine_diff_density_max         0.416
_refine_diff_density_min         -0.500
_refine_diff_density_rms         0.111
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.991
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     229
_refine_ls_number_reflns         3989
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.991
_refine_ls_R_factor_all          0.0628
_refine_ls_R_factor_gt           0.0417
_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^)+(0.0400P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0964
_refine_ls_wR_factor_ref         0.1092
_reflns_number_gt                2797
_reflns_number_total             3989
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c3ob41028e.txt
_cod_data_source_block           shelx
_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 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 1891 2012-01-12 08:04:46Z andrius 
;
_cod_original_cell_volume        1666.5(11)
_cod_original_sg_symbol_H-M      P2(1)/c
_cod_database_code               7153040