Simple Total Synthesis of the Pentacyclic Cs-Symmetric Structure Attributed to the Squalenoid Glabrescol and Three Cs-Symmetric Diastereomers Compel Structural Revision
Zhaoming Xiong; E. J. Corey; Journal of the American Chemical Society 122 (2000) 4831–4832; doi:10.1021/ja000842y

data_4116003
_publ_section_title
;
 Simple Total Synthesis of the Pentacyclic Cs-Symmetric Structure
 Attributed to the Squalenoid Glabrescol and Three Cs-Symmetric
 Diastereomers Compel Structural Revision
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              4831
_journal_page_last               4832
_journal_paper_doi               10.1021/ja000842y
_journal_volume                  122
_journal_year                    2000
_chemical_formula_sum            'C44 H58 Br2 O9'
_chemical_formula_weight         890.72
_chemical_melting_point          415(1)
_chemical_name_systematic
;
(3R,6S,7R,10S,11R,14S,15R,18S,19R,22S)-2,23-bis(4'-bromobenzoyloxy)-2,6,10,1
5,19,23-hexamethyl-3,7,11,15,19-penta(oxacyclopentyl)tetracosane
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 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                 100.25(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   15.703(10)
_cell_length_b                   6.639(3)
_cell_length_c                   42.24(3)
_cell_measurement_reflns_used    0
_cell_measurement_temperature    213(2)
_cell_measurement_theta_max      0.00
_cell_measurement_theta_min      0.00
_cell_volume                     4333(5)
_computing_cell_refinement       'SMART (Bruker, V4.050, 1995)'
_computing_data_collection       'ASTRO (Bruker, V4.050, 1995)'
_computing_data_reduction        'SAINT (Bruker, V5.A06, 1997)'
_computing_molecular_graphics    'SHELXTL (Bruker, 1998, ver 5.10)'
_computing_publication_material  'CIFTAB (Sheldrick, 1993)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      213(2)
_diffrn_measured_fraction_theta_full 0.858
_diffrn_measured_fraction_theta_max 0.858
_diffrn_measurement_method       '\w, 0.3 deg'
_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  0.1429
_diffrn_reflns_av_sigmaI/netI    0.3237
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -3
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       52
_diffrn_reflns_limit_l_min       -56
_diffrn_reflns_number            12868
_diffrn_reflns_theta_full        28.34
_diffrn_reflns_theta_max         28.34
_diffrn_reflns_theta_min         0.98
_diffrn_standards_decay_%        <1
_diffrn_standards_interval_count 0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    1.923
_exptl_absorpt_correction_T_max  0.000000
_exptl_absorpt_correction_T_min  0.000000
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            clear
_exptl_crystal_density_diffrn    1.365
_exptl_crystal_description       plates
_exptl_crystal_F_000             1856
_exptl_crystal_size_max          0.0034
_exptl_crystal_size_mid          0.002
_exptl_crystal_size_min          0.001
_refine_diff_density_max         0.434
_refine_diff_density_min         -0.382
_refine_diff_density_rms         0.078
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.979
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     496
_refine_ls_number_reflns         9269
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.979
_refine_ls_R_factor_all          0.3532
_refine_ls_R_factor_gt           0.1159
_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^)+(0.0800P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1908
_refine_ls_wR_factor_ref         0.2851
_reflns_number_gt                2467
_reflns_number_total             9269
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja000842y.cif
_cod_data_source_block           zmg1
_cod_original_cell_volume        4333(4)
_cod_database_code               4116003