Highly diastereoselective and enantioselective formal [4 + 3] cycloaddition of donor-acceptor cyclobutanes with nitrones.
Hu, Jiang-Lin; Wang, Lijia; Xu, Hao; Xie, Zuowei; Tang, Yong; Organic letters 17 (2015) 2680–2683; doi:10.1021/acs.orglett.5b01077

data_1519658
_publ_section_title
;
 Highly diastereoselective and enantioselective formal [4 + 3]
 cycloaddition of donor-acceptor cyclobutanes with nitrones.
;
_journal_issue                   11
_journal_name_full               'Organic letters'
_journal_page_first              2680
_journal_page_last               2683
_journal_paper_doi               10.1021/acs.orglett.5b01077
_journal_volume                  17
_journal_year                    2015
_chemical_absolute_configuration ad
_chemical_formula_sum            'C28 H28 Br N O6'
_chemical_formula_weight         554.42
_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                   10.4090(7)
_cell_length_b                   15.4718(11)
_cell_length_c                   16.5880(11)
_cell_measurement_reflns_used    3332
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      43.430
_cell_measurement_theta_min      4.620
_cell_volume                     2671.4(3)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_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  0.0368
_diffrn_reflns_av_sigmaI/netI    0.0606
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            16249
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         26.00
_diffrn_reflns_theta_min         1.80
_exptl_absorpt_coefficient_mu    1.580
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.19709
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.379
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             1144
_exptl_crystal_size_max          0.211
_exptl_crystal_size_mid          0.167
_exptl_crystal_size_min          0.121
_refine_diff_density_max         0.456
_refine_diff_density_min         -0.414
_refine_diff_density_rms         0.040
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.008(9)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.020
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     328
_refine_ls_number_reflns         5233
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.020
_refine_ls_R_factor_all          0.0661
_refine_ls_R_factor_gt           0.0414
_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^)+(0.0404P)^2^+0.0696P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0930
_refine_ls_wR_factor_ref         0.1023
_reflns_number_gt                3690
_reflns_number_total             5233
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol5b01077_si_002.cif
_cod_data_source_block           cd213507
_cod_depositor_comments
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The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/usr/data/users/saulius/crontab/automatic-downloads/rss-feeds/ACS/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 3271 2015-04-21 07:52:19Z andrius 

 Adding full bibliography for 1519657--1519658.cif.
;
_cod_original_sg_symbol_H-M      P2(1)2(1)2(1)
_cod_database_code               1519658