Benzyne-Mediated Nonconcerted Pathway toward Synthesis of Sterically Crowded [5]- and [7]Oxahelicenoids, Stereochemical and Theoretical Studies, and Optical Resolution of Helicenoids.
Gawade, Prashant M.; Khose, Vaibhav N.; Badani, Purav M.; Hasan, Mohammed; Kaabel, Sandra; Mobin, Shaikh M.; Borovkov, Victor; Karnik, Anil V.; The Journal of organic chemistry 84 (2019) 860–868; doi:10.1021/acs.joc.8b02507

data_4036000
_publ_section_title
;
 Benzyne-Mediated Nonconcerted Pathway toward Synthesis of Sterically
 Crowded [5]- and [7]Oxahelicenoids, Stereochemical and Theoretical
 Studies, and Optical Resolution of Helicenoids.
;
_journal_issue                   2
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              860
_journal_page_last               868
_journal_paper_doi               10.1021/acs.joc.8b02507
_journal_volume                  84
_journal_year                    2019
_chemical_formula_moiety         'C28 H22 O4'
_chemical_formula_sum            'C28 H22 O4'
_chemical_formula_weight         422.45
_chemical_name_systematic
;
9,9'-dimethoxy-3H,3'H-1,1'-bibenzo[f]chromene
;
_space_group_crystal_system      orthorhombic
_space_group_IT_number           61
_space_group_name_Hall           '-P 2ac 2ab'
_space_group_name_H-M_alt        'P b c a'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2017-08-08
_audit_creation_method
;
Olex2 1.2
(compiled 2017.07.20 svn.r3457 for OlexSys, GUI svn.r5370)
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   12.48030(10)
_cell_length_b                   17.48770(10)
_cell_length_c                   18.5699(2)
_cell_measurement_reflns_used    19462
_cell_measurement_temperature    123(2)
_cell_measurement_theta_max      67.2060
_cell_measurement_theta_min      3.4570
_cell_volume                     4052.91(6)
_computing_cell_refinement       'CrysAlisPro 1.171.38.43 (Rigaku OD, 2015)'
_computing_data_collection
;
Rigaku Collection Strategy
(Daniels, L. M. (2011). Acta Cryst. A67, C143)
;
_computing_data_reduction        'CrysAlisPro 1.171.38.43 (Rigaku OD, 2015)'
_computing_molecular_graphics
;
Mercury CSD 3.9 (Macrae, C. F., et al. (2006). J. Appl. Cryst. 39, 453-457)
POV-Ray 3.7 (Persistence of Vision Pty. Ltd. (2004)) 
;
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'ShelXL (Sheldrick, 2015)'
_computing_structure_solution    'ShelXT (Sheldrick, 2015)'
_diffrn_ambient_temperature      123.0
_diffrn_detector                 'CCD plate'
_diffrn_measured_fraction_theta_full 0.992
_diffrn_measured_fraction_theta_max 0.992
_diffrn_measurement_details
;
List of Runs (angles in degrees, time in seconds):

  # Type    Start    End  Width  t~exp~   \w     \q     \k     \f   Frames
--------------------------------------------------------------------------
  1  \w   -179.00   0.00   1.00   10.00    --  -90.00  60.00-180.00  179
  2  \w   -110.00  69.00   1.00   10.00    --  -21.00  60.00 -36.00  179
  3  \w   -179.00   0.00   1.00   10.00    --  -90.00  30.00  36.00  179
  4  \w   -179.00   0.00   1.00   10.00    --  -90.00  60.00 -36.00  179
  5  \w   -179.00   0.00   1.00   10.00    --  -90.00  60.00  36.00  179
  6  \w   -179.00   0.00   1.00   10.00    --  -90.00  30.00-108.00  179
  7  \w   -179.00   0.00   1.00   10.00    --  -90.00  60.00-108.00  179
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'Rigaku Saturn944+ (2x2 bin mode)'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      0.0588892000
_diffrn_orient_matrix_UB_12      -0.0688459000
_diffrn_orient_matrix_UB_13      -0.0333572000
_diffrn_orient_matrix_UB_21      0.0045779000
_diffrn_orient_matrix_UB_22      -0.0386759000
_diffrn_orient_matrix_UB_23      0.0744338000
_diffrn_orient_matrix_UB_31      -0.1084696000
_diffrn_orient_matrix_UB_32      -0.0390265000
_diffrn_orient_matrix_UB_33      -0.0149395000
_diffrn_radiation_monochromator  Confocal
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.0305
_diffrn_reflns_av_unetI/netI     0.0126
_diffrn_reflns_Laue_measured_fraction_full 0.992
_diffrn_reflns_Laue_measured_fraction_max 0.992
_diffrn_reflns_limit_h_max       14
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_k_max       20
_diffrn_reflns_limit_k_min       -20
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            35848
_diffrn_reflns_point_group_measured_fraction_full 0.992
_diffrn_reflns_point_group_measured_fraction_max 0.992
_diffrn_reflns_theta_full        67.327
_diffrn_reflns_theta_max         67.327
_diffrn_reflns_theta_min         4.962
_diffrn_source                   'fine-focus sealed X-ray tube'
_diffrn_source_type              'Rigaku MicroMax-003'
_exptl_absorpt_coefficient_mu    0.740
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.55684
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.38.43 (Rigaku Oxford Diffraction, 2015)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            'light yellow'
_exptl_crystal_colour_modifier   light
_exptl_crystal_colour_primary    yellow
_exptl_crystal_density_diffrn    1.385
_exptl_crystal_description       block
_exptl_crystal_F_000             1776
_exptl_crystal_size_max          0.4
_exptl_crystal_size_mid          0.17
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.351
_refine_diff_density_min         -0.208
_refine_diff_density_rms         0.040
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.032
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     291
_refine_ls_number_reflns         3610
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.032
_refine_ls_R_factor_all          0.0450
_refine_ls_R_factor_gt           0.0427
_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^)+(0.0690P)^2^+1.7305P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1159
_refine_ls_wR_factor_ref         0.1180
_reflns_Friedel_coverage         0.000
_reflns_number_gt                3388
_reflns_number_total             3610
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo8b02507_si_002.cif
_cod_data_source_block           compound_1
_cod_database_code               4036000
_shelx_shelxl_version_number     2016/6
_chemical_oxdiff_formula         'C26 H12 O2'
_reflns_odcompleteness_completeness 99.24
_reflns_odcompleteness_iscentric 1
_reflns_odcompleteness_theta     67.21
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Secondary CH2 refined with riding coordinates:
 C3(H3A,H3B), C3S(H3SA,H3SB)
2.b Aromatic/amide H refined with riding coordinates:
 C10(H10), C8(H8), C7(H7), C6(H6), C5(H5), C2(H2), C2S(H2S), C5S(H5S),
 C6S(H6S), C7S(H7S), C8S(H8S), C10S(H10S)
2.c Idealised Me refined as rotating group:
 C11(H11A,H11B,H11C), C11S(H11D,H11E,H11F)
;
_shelx_res_checksum              35057
_shelx_hkl_checksum              87381
_olex2_submission_special_instructions 'No special instructions were received'
_oxdiff_exptl_absorpt_empirical_details
;
Empirical correction (ABSPACK) includes:
- Absorption correction using spherical harmonics
- Frame scaling
- Detector area scaling
;
_oxdiff_exptl_absorpt_empirical_full_max 1.502
_oxdiff_exptl_absorpt_empirical_full_min 0.536