Alkaloid-Catalyzed Enantioselective [3 + 2] Cycloaddition of Ketenes and Azomethine Imines.
Mondal, Mukulesh; Wheeler, Kraig A.; Kerrigan, Nessan J.; Organic letters 18 (2016) 4108–4111; doi:10.1021/acs.orglett.6b02038

data_1555677
_publ_section_title
;
 Alkaloid-Catalyzed Enantioselective [3 + 2] Cycloaddition of Ketenes and
 Azomethine Imines.
;
_journal_issue                   16
_journal_name_full               'Organic letters'
_journal_page_first              4108
_journal_page_last               4111
_journal_paper_doi               10.1021/acs.orglett.6b02038
_journal_volume                  18
_journal_year                    2016
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C14 H14 N2 O4'
_chemical_formula_sum            'C14 H14 N2 O4'
_chemical_formula_weight         274.27
_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'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   6.7657(2)
_cell_length_b                   12.1602(3)
_cell_length_c                   16.0507(4)
_cell_measurement_reflns_used    6559
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      67.80
_cell_measurement_theta_min      4.56
_cell_volume                     1320.53(6)
_computing_cell_refinement       APEX2
_computing_data_collection       'APEX2 (Bruker, 2013)'
_computing_data_reduction
;
SADABS (Bruker, 2013) and XPREP (Bruker, 2013)
;
_computing_molecular_graphics    'XSEED (Barbour, 2001)'
_computing_publication_material  'XSEED (Barbour, 2001)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_diffrn_ambient_temperature      100(2)
_diffrn_detector_area_resol_mean 8.33
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker APEXII CCD'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0354
_diffrn_reflns_av_unetI/netI     0.0167
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 1.000
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       19
_diffrn_reflns_limit_l_min       -19
_diffrn_reflns_number            19856
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 1.000
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         68.175
_diffrn_reflns_theta_min         4.562
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.857
_exptl_absorpt_correction_T_max  0.753
_exptl_absorpt_correction_T_min  0.700
_exptl_absorpt_process_details   'SADABS-2014/7, Bruker AXS'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.380
_exptl_crystal_description       'transparent rod'
_exptl_crystal_F_000             576
_exptl_crystal_size_max          0.197
_exptl_crystal_size_mid          0.156
_exptl_crystal_size_min          0.094
_refine_diff_density_max         0.126
_refine_diff_density_min         -0.135
_refine_diff_density_rms         0.029
_refine_ls_abs_structure_details
;
 Flack x determined using 941 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.12(7)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.054
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     182
_refine_ls_number_reflns         2416
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.054
_refine_ls_R_factor_all          0.0275
_refine_ls_R_factor_gt           0.0261
_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^)+(0.0437P)^2^+0.1357P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0692
_refine_ls_wR_factor_ref         0.0702
_reflns_Friedel_coverage         0.705
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     1.000
_reflns_number_gt                2322
_reflns_number_total             2416
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ol6b02038_si_004.cif
_cod_data_source_block           nker21
_cod_database_code               1555677
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.849
_shelx_estimated_absorpt_t_max   0.924
_shelx_res_checksum              48099
_shelx_hkl_checksum              68965