Photochemical [2 + 2] cycloaddition reactions of 6-alkenyl-3-phenylcyclohex-2-en-1-ones: using biradical conformation control to account for exceptions to the "rule of five".
Bradley, Stephen A.; Bresnan, Brian J.; Draper, Sylvia M.; Geraghty, Niall W. A.; Jeffares, Mark; McCabe, Thomas; McMurry, T Brian H; O'Brien, John E; Organic & biomolecular chemistry 9 (2011) 2959–2968; doi:10.1039/c0ob01131b

data_7151817
_publ_section_title
;
 Photochemical [2 + 2] cycloaddition reactions of
 6-alkenyl-3-phenylcyclohex-2-en-1-ones: using biradical conformation
 control to account for exceptions to the "rule of five".
;
_journal_issue                   8
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              2959
_journal_page_last               2968
_journal_paper_doi               10.1039/c0ob01131b
_journal_volume                  9
_journal_year                    2011
_chemical_formula_sum            'C18 H20 O3'
_chemical_formula_weight         284.34
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                102.795(8)
_cell_angle_beta                 99.112(11)
_cell_angle_gamma                105.356(9)
_cell_formula_units_Z            2
_cell_length_a                   6.6572(9)
_cell_length_b                   9.8399(8)
_cell_length_c                   12.3209(15)
_cell_measurement_temperature    293(2)
_cell_volume                     738.47(16)
_computing_cell_refinement       'CAD4 Express (Enraf Nonius, 1994)'
_computing_data_collection       'CAD4 Express (Enraf Nonius, 1994)'
_computing_data_reduction        'XCAD4 (Harms & Wocadlo, 1995)'
_computing_molecular_graphics    Shelxtl
_computing_publication_material  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 0.977
_diffrn_measured_fraction_theta_max 0.977
_diffrn_measurement_device_type  'Enraf Nonius CAD4'
_diffrn_measurement_method       'non-profiled omega/2theta 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  0.0325
_diffrn_reflns_av_sigmaI/netI    0.0756
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       0
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            2763
_diffrn_reflns_theta_full        24.97
_diffrn_reflns_theta_max         24.97
_diffrn_reflns_theta_min         1.74
_exptl_absorpt_coefficient_mu    0.086
_exptl_absorpt_correction_T_max  0.9665
_exptl_absorpt_correction_T_min  0.9503
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   Sadabs
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.279
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             304
_exptl_crystal_size_max          0.60
_exptl_crystal_size_mid          0.40
_exptl_crystal_size_min          0.40
_refine_diff_density_max         0.161
_refine_diff_density_min         -0.160
_refine_diff_density_rms         0.042
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.991
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     259
_refine_ls_number_reflns         2529
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.991
_refine_ls_R_factor_all          0.1289
_refine_ls_R_factor_gt           0.0513
_refine_ls_shift/su_max          0.006
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0581P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1022
_refine_ls_wR_factor_ref         0.1254
_reflns_number_gt                1396
_reflns_number_total             2529
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c0ob01131b.txt
_cod_data_source_block           mcmcs
_cod_depositor_comments
;
The following automatic conversions were performed:
'_symmetry_cell_setting' value 'Triclinic' changed to 'triclinic'
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_enum 1555 2011-01-17 13:19:09Z saulius 
;
_cod_original_cell_volume        738.47(15)
_cod_original_sg_symbol_H-M      P-1
_cod_database_code               7151817