Thermally induced electrocyclic reaction of methylenecyclopropane methylene diketone derivatives: a facile method for the synthesis of spiro[2.5]octa-3,5-dienes.
Tang, Xiang-Ying; Wei, Yin; Shi, Min; Organic letters 12 (2010) 5120–5123; doi:10.1021/ol102002f

data_1503246
_publ_section_title
;
 Thermally induced electrocyclic reaction of methylenecyclopropane
 methylene diketone derivatives: a facile method for the synthesis of
 spiro[2.5]octa-3,5-dienes.
;
_journal_issue                   22
_journal_name_full               'Organic letters'
_journal_page_first              5120
_journal_page_last               5123
_journal_paper_doi               10.1021/ol102002f
_journal_volume                  12
_journal_year                    2010
_chemical_formula_sum            'C19 H19 Br O2'
_chemical_formula_weight         359.25
_space_group_IT_number           60
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2n 2ab'
_symmetry_space_group_name_H-M   'P b c n'
_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            8
_cell_length_a                   25.683(3)
_cell_length_b                   12.1372(13)
_cell_length_c                   11.0178(12)
_cell_measurement_reflns_used    1681
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      37.604
_cell_measurement_theta_min      5.239
_cell_volume                     3434.5(7)
_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 0.999
_diffrn_measured_fraction_theta_max 0.999
_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  0.0982
_diffrn_reflns_av_sigmaI/netI    0.0845
_diffrn_reflns_limit_h_max       26
_diffrn_reflns_limit_h_min       -31
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            17036
_diffrn_reflns_theta_full        25.50
_diffrn_reflns_theta_max         25.50
_diffrn_reflns_theta_min         1.86
_exptl_absorpt_coefficient_mu    2.398
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.4643
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.390
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             1472
_exptl_crystal_size_max          0.396
_exptl_crystal_size_mid          0.267
_exptl_crystal_size_min          0.175
_refine_diff_density_max         0.564
_refine_diff_density_min         -0.730
_refine_diff_density_rms         0.047
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   0.941
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     202
_refine_ls_number_reflns         3201
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.941
_refine_ls_R_factor_all          0.1220
_refine_ls_R_factor_gt           0.0488
_refine_ls_shift/su_max          0.004
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
; calc 
 [0.00000+1.00000exp(2.00(sin\q/\l)^2^)]/ 
   [\s^2^(Fo^2^)+0.0000+0.0000*P+(0.0711P)^2^+0.0000sin\q/\l] 
 where P = 0.33333Fo^2^ + 0.66667Fc^2^ 
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1294
_refine_ls_wR_factor_ref         0.1556
_reflns_number_gt                1260
_reflns_number_total             3201
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol102002f_si_001.cif
_cod_data_source_block           cd29608
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_cell_volume        3434.5(6)
_cod_original_sg_symbol_H-M      Pbcn
_cod_database_code               1503246