NHC-catalyzed enantioselective [2 + 2] and [2 + 2 + 2] cycloadditions of ketenes with isothiocyanates.
Wang, Xiao-Na; Shen, Li-Tao; Ye, Song; Organic letters 13 (2011) 6382–6385; doi:10.1021/ol202688h

data_1502594
_publ_section_title
;
 NHC-catalyzed enantioselective [2 + 2] and [2 + 2 + 2] cycloadditions of
 ketenes with isothiocyanates.
;
_journal_issue                   24
_journal_name_full               'Organic letters'
_journal_page_first              6382
_journal_page_last               6385
_journal_paper_doi               10.1021/ol202688h
_journal_volume                  13
_journal_year                    2011
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C27 H24 N2 O4 S'
_chemical_formula_sum            'C27 H24 N2 O4 S'
_chemical_formula_weight         472.54
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   7.6443(15)
_cell_length_b                   9.925(2)
_cell_length_c                   31.114(6)
_cell_measurement_reflns_used    7056
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      27.4819
_cell_measurement_theta_min      1.3089
_cell_volume                     2360.6(8)
_computing_cell_refinement       'CrystalClear (Rigaku Inc., 2008)'
_computing_data_collection       'CrystalClear (Rigaku Inc., 2008)'
_computing_data_reduction        'CrystalClear (Rigaku Inc., 2008)'
_computing_molecular_graphics
;
 Mercury: visualization and analysis of crystal structures, C. F. Macrae,
 P. R. Edgington, P. McCabe, E. Pidcock, G. P. Shields, R. Taylor,
 M. Towler and J. van de Streek, J. Appl. Cryst., 39, 453-457, 2006.
;
_computing_publication_material  'SHELX-97 (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      173(2)
_diffrn_detector_area_resol_mean 28.5714
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'MM007HF + CCD (Saturn724+)'
_diffrn_measurement_method       '\w scans at fixed \c = 45\%'
_diffrn_radiation_monochromator  Confocal
_diffrn_radiation_source         'Rotating Anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0417
_diffrn_reflns_av_sigmaI/netI    0.0450
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       36
_diffrn_reflns_limit_l_min       -40
_diffrn_reflns_number            15358
_diffrn_reflns_theta_full        27.48
_diffrn_reflns_theta_max         27.48
_diffrn_reflns_theta_min         2.15
_exptl_absorpt_coefficient_mu    0.174
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.6957
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'CrystalClear (Rigaku Inc., 2008)'
_exptl_crystal_colour            Colorless
_exptl_crystal_density_diffrn    1.330
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             992
_exptl_crystal_size_max          0.18
_exptl_crystal_size_mid          0.16
_exptl_crystal_size_min          0.11
_refine_diff_density_max         0.198
_refine_diff_density_min         -0.176
_refine_diff_density_rms         0.039
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.03(7)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.092
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     309
_refine_ls_number_reflns         5389
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.092
_refine_ls_R_factor_all          0.0508
_refine_ls_R_factor_gt           0.0466
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0241P)^2^+0.6494P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0883
_refine_ls_wR_factor_ref         0.0906
_reflns_number_gt                5020
_reflns_number_total             5389
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol202688h_si_003.cif
_cod_data_source_block           a
_cod_original_cell_volume        2360.7(8)
_cod_original_sg_symbol_H-M      P2(1)2(1)2(1)
_cod_database_code               1502594