Formation of an Endoperoxide upon Chromium-Catalyzed Allylic Oxidation of a Triterpene by Oxygen.
Chung, Abbie; Miner, Matthew R.; Richert, Kathleen J.; Rieder, Curtis J.; Woerpel, K. A.; The Journal of organic chemistry 80 (2014) 266–; doi:10.1021/jo502344x

data_4030293
_publ_section_title
;
 Formation of an Endoperoxide upon Chromium-Catalyzed Allylic Oxidation of
 a Triterpene by Oxygen.
;
_journal_issue                   1
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              266
_journal_paper_doi               10.1021/jo502344x
_journal_volume                  80
_journal_year                    2014
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C31 H44 O5'
_chemical_formula_sum            'C31 H44 O5'
_chemical_formula_weight         496.66
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_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                   7.4322(4)
_cell_length_b                   22.4492(14)
_cell_length_c                   32.2193(19)
_cell_measurement_reflns_used    9917
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      25.74
_cell_measurement_theta_min      2.21
_cell_volume                     5375.7(5)
_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      100(2)
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_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  0.0808
_diffrn_reflns_av_sigmaI/netI    0.0318
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       28
_diffrn_reflns_limit_k_min       -28
_diffrn_reflns_limit_l_max       41
_diffrn_reflns_limit_l_min       -41
_diffrn_reflns_number            117028
_diffrn_reflns_theta_full        27.13
_diffrn_reflns_theta_max         27.13
_diffrn_reflns_theta_min         1.56
_exptl_absorpt_coefficient_mu    0.081
_exptl_absorpt_correction_T_max  0.9943
_exptl_absorpt_correction_T_min  0.9559
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.227
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             2160
_exptl_crystal_size_max          0.56
_exptl_crystal_size_mid          0.27
_exptl_crystal_size_min          0.07
_refine_diff_density_max         0.236
_refine_diff_density_min         -0.194
_refine_diff_density_rms         0.043
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.056
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     664
_refine_ls_number_reflns         6665
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.056
_refine_ls_R_factor_all          0.0513
_refine_ls_R_factor_gt           0.0403
_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^)+(0.0443P)^2^+2.0489P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0913
_refine_ls_wR_factor_ref         0.0965
_reflns_number_gt                5798
_reflns_number_total             6665
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            jo502344x_si_003.cif
_cod_data_source_block           11kaw4h
_cod_depositor_comments
'Adding full bibliography for 4030293--4030296.cif.'
_cod_database_code               4030293