Gassman's intramolecular [2 + 2] cationic cycloaddition. formal total syntheses of raikovenal and epi-raikovenal.
Ko, Changhong; Feltenberger, John B.; Ghosh, Sunil K.; Hsung, Richard P.; Organic letters 10 (2008) 1971–1974; doi:10.1021/ol8004968

data_1504645
_publ_section_title
;
 Gassman's intramolecular [2 + 2] cationic cycloaddition. formal total
 syntheses of raikovenal and epi-raikovenal.
;
_journal_issue                   10
_journal_name_full               'Organic letters'
_journal_page_first              1971
_journal_page_last               1974
_journal_paper_doi               10.1021/ol8004968
_journal_volume                  10
_journal_year                    2008
_chemical_formula_moiety         'C17 H21 Br O3'
_chemical_formula_sum            'C17 H21 Br O3'
_chemical_formula_weight         353.25
_chemical_name_common            05350
_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                93.308(2)
_cell_angle_beta                 96.276(2)
_cell_angle_gamma                93.402(2)
_cell_formula_units_Z            2
_cell_length_a                   7.0187(6)
_cell_length_b                   7.9272(7)
_cell_length_c                   14.4217(13)
_cell_measurement_reflns_used    2789
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      25.00
_cell_measurement_theta_min      2.58
_cell_volume                     794.52(12)
_computing_cell_refinement       'SAINT, Bruker'
_computing_data_collection       'SMART, Bruker'
_computing_data_reduction        'SAINT, Bruker'
_computing_molecular_graphics    'SHELXTL, Bruker'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'Siemens SMART Platform CCD'
_diffrn_measurement_method       'area detector, omega scans per phi'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'normal-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0382
_diffrn_reflns_av_sigmaI/netI    0.0545
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            6652
_diffrn_reflns_theta_full        25.06
_diffrn_reflns_theta_max         25.06
_diffrn_reflns_theta_min         1.42
_exptl_absorpt_coefficient_mu    2.594
_exptl_absorpt_correction_T_max  0.8812
_exptl_absorpt_correction_T_min  0.5099
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS, R. Blessing, 1995'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.477
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             364
_exptl_crystal_size_max          0.30
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.554
_refine_diff_density_min         -0.413
_refine_diff_density_rms         0.074
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.020
_refine_ls_hydrogen_treatment    riding
_refine_ls_matrix_type           full
_refine_ls_number_parameters     192
_refine_ls_number_reflns         2799
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.020
_refine_ls_R_factor_all          0.0629
_refine_ls_R_factor_gt           0.0404
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0441P)^2^+0.3186P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0839
_refine_ls_wR_factor_ref         0.0921
_reflns_number_gt                2184
_reflns_number_total             2799
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol8004968-file005.cif
_cod_data_source_block           05350
_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_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_sg_symbol_H-M      P-1
_cod_database_code               1504645