Sydnone-Based Approach to Heterohelicenes through 1,3-Dipolar-Cycloadditions.
Yen-Pon, Expédite; Champagne, Pier Alexandre; Plougastel, Lucie; Gabillet, Sandra; Thuéry, Pierre; Johnson, Mizuki; Muller, Gilles; Pieters, Grégory; Taran, Frédéric; Houk, K. N.; Audisio, Davide; Journal of the American Chemical Society 141 (2019) 1435–1440; doi:10.1021/jacs.8b11465

data_4128050
_publ_section_title
;
 Sydnone-Based Approach to Heterohelicenes through
 1,3-Dipolar-Cycloadditions.
;
_journal_issue                   4
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              1435
_journal_page_last               1440
_journal_paper_doi               10.1021/jacs.8b11465
_journal_volume                  141
_journal_year                    2019
_chemical_absolute_configuration unk
_chemical_formula_sum            'C21 H14 N2'
_chemical_formula_weight         294.34
_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'
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   '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                   4.9489(2)
_cell_length_b                   12.6503(4)
_cell_length_c                   23.4534(8)
_cell_measurement_reflns_used    55497
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      28.70
_cell_measurement_theta_min      3.22
_cell_volume                     1468.30(9)
_computing_cell_refinement       'HKL2000 (Otwinowski & Minor, 1997)'
_computing_data_collection       'COLLECT (Nonius, 1998)'
_computing_data_reduction        'HKL2000 (Otwinowski & Minor, 1997)'
_computing_molecular_graphics    'SHELXTL (Sheldrick, 2008)'
_computing_publication_material
'SHELXTL (Sheldrick, 2008); PLATON (Spek, 2003)'
_computing_structure_refinement  'SHELXL (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT (Sheldrick, 2015)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type  'Nonius Kappa-CCD area-detector diffractometer'
_diffrn_measurement_method
'two \f and seven \w scans with 1\% steps (1111 frames)'
_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  0.0154
_diffrn_reflns_av_unetI/netI     0.0177
_diffrn_reflns_Laue_measured_fraction_full 0.994
_diffrn_reflns_Laue_measured_fraction_max 0.996
_diffrn_reflns_limit_h_max       6
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            55497
_diffrn_reflns_point_group_measured_fraction_full 0.592
_diffrn_reflns_point_group_measured_fraction_max 0.583
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.696
_diffrn_reflns_theta_min         3.221
_diffrn_standards_decay_%        0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.079
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            yellow-brown
_exptl_crystal_density_diffrn    1.332
_exptl_crystal_description       parallelepiped
_exptl_crystal_F_000             616
_exptl_crystal_size_max          0.24
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.16
_refine_diff_density_max         0.149
_refine_diff_density_min         -0.173
_refine_diff_density_rms         0.038
_refine_ls_abs_structure_details
;
In the absence of a suitable anomalous scatterer, the Friedel
pairs have been merged.
;
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.064
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     245
_refine_ls_number_reflns         2219
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.066
_refine_ls_R_factor_all          0.0433
_refine_ls_R_factor_gt           0.0362
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0642P)^2^+0.0464P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0934
_refine_ls_wR_factor_ref         0.0969
_reflns_Friedel_coverage         0.000
_reflns_Friedel_fraction_full    0.000
_reflns_Friedel_fraction_max     0.000
_reflns_number_gt                1933
_reflns_number_total             2219
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja8b11465_si_002.cif
_cod_data_source_block           11b
_cod_database_code               4128050
_shelxl_version_number           2014-3
_shelx_res_checksum              65185
_shelx_hkl_checksum              15108