The formal [4+3] cycloaddition between donor-acceptor cyclobutanes and nitrones.
Stevens, Andrew C.; Palmer, Cory; Pagenkopf, Brian L.; Organic letters 13 (2011) 1528–1531; doi:10.1021/ol200220d

data_1502061
_publ_section_title
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 The formal [4+3] cycloaddition between donor-acceptor cyclobutanes and
 nitrones.
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_journal_issue                   6
_journal_name_full               'Organic letters'
_journal_page_first              1528
_journal_page_last               1531
_journal_paper_doi               10.1021/ol200220d
_journal_volume                  13
_journal_year                    2011
_chemical_formula_moiety         'C25 H28 Cl N O6'
_chemical_formula_sum            'C25 H28 Cl N O6'
_chemical_formula_weight         473.93
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_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                 96.924(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   13.1053(7)
_cell_length_b                   11.2478(6)
_cell_length_c                   16.0248(9)
_cell_measurement_reflns_used    9891
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      23.84
_cell_measurement_theta_min      2.39
_cell_volume                     2344.9(2)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w 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  0.0864
_diffrn_reflns_av_sigmaI/netI    0.0355
_diffrn_reflns_limit_h_max       17
_diffrn_reflns_limit_h_min       -17
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            112617
_diffrn_reflns_theta_full        28.28
_diffrn_reflns_theta_max         28.28
_diffrn_reflns_theta_min         1.90
_exptl_absorpt_coefficient_mu    0.204
_exptl_absorpt_correction_T_max  0.9731
_exptl_absorpt_correction_T_min  0.9593
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.342
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1000
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.17
_exptl_crystal_size_min          0.13
_refine_diff_density_max         0.367
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_refine_ls_extinction_method     none
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_refine_ls_matrix_type           full
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_refine_ls_number_reflns         5812
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_refine_ls_restrained_S_all      1.013
_refine_ls_R_factor_all          0.0680
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_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^)+(0.0330P)^2^+1.3489P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0829
_refine_ls_wR_factor_ref         0.0962
_reflns_number_gt                4183
_reflns_number_total             5812
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol200220d_si_005.cif
_cod_data_source_block           b10121_0m
_cod_depositor_comments
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The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
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_cod_original_sg_symbol_H-M      P2(1)/n
_cod_database_code               1502061