Bismuth triflate-catalyzed Wagner-Meerwein rearrangement in terpenes. Application to the synthesis of the 18α-oleanane core and A-neo-18α-oleanene compounds from lupanes
Salvador, Jorge A. R.; Pinto, Rui M. A.; Santos, Rita C.; Le Roux, Christophe; Beja, Ana Matos; Paixão, José A.; Organic & Biomolecular Chemistry 7 (2009) 508–517; doi:10.1039/b814448f

data_7150533
_publ_section_title
;
 Bismuth triflate-catalyzed Wagner-Meerwein rearrangement in terpenes.
 Application to the synthesis of the 18\a-oleanane core and
 A-neo-18\a-oleanene compounds from lupanes
;
_journal_issue                   3
_journal_name_full               'Organic &amp; Biomolecular Chemistry'
_journal_page_first              508
_journal_page_last               517
_journal_paper_doi               10.1039/b814448f
_journal_volume                  7
_journal_year                    2009
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C32 H52 O3'
_chemical_formula_sum            'C32 H52 O3'
_chemical_formula_weight         484.76
_chemical_melting_point          559
_chemical_name_systematic
;
19\b,28-epoxy-18\a-olean-3\b-yl acetate
;
_space_group_IT_number           5
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'C 2y'
_symmetry_space_group_name_H-M   'C 1 2 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                 99.0080(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   13.3520(2)
_cell_length_b                   6.54000(10)
_cell_length_c                   32.4439(5)
_cell_measurement_reflns_used    9681
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      26.1742
_cell_measurement_theta_min      2.5425
_cell_volume                     2798.13(7)
_computing_cell_refinement       'SAINT (Bruker, 2003)'
_computing_data_collection       'SMART (Bruker, 2003)'
_computing_data_reduction        'SAINT (Bruker, 2003)'
_computing_molecular_graphics    'PLATON (Spek, 2005)'
_computing_publication_material  SHELXL-97
_computing_structure_refinement  SHELXL-97
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker APEX CCD area-detector'
_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  0.0268
_diffrn_reflns_av_sigmaI/netI    0.0137
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       40
_diffrn_reflns_limit_l_min       -40
_diffrn_reflns_number            26879
_diffrn_reflns_theta_full        25.50
_diffrn_reflns_theta_max         26.24
_diffrn_reflns_theta_min         1.91
_exptl_absorpt_coefficient_mu    0.071
_exptl_absorpt_correction_T_max  0.989
_exptl_absorpt_correction_T_min  0.934
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(SADABS; Sheldrick, 2000)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.151
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       tabular
_exptl_crystal_F_000             1072
_exptl_crystal_size_max          0.36
_exptl_crystal_size_mid          0.24
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.184
_refine_diff_density_min         -0.126
_refine_diff_density_rms         0.027
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.5(14)
_refine_ls_extinction_coef       0.0014(5)
_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   1.036
_refine_ls_hydrogen_treatment    riding
_refine_ls_matrix_type           full
_refine_ls_number_parameters     325
_refine_ls_number_reflns         3074
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.035
_refine_ls_R_factor_all          0.0408
_refine_ls_R_factor_gt           0.0355
_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^)+(0.0600P)^2^+0.5416P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0951
_refine_ls_wR_factor_ref         0.0994
_reflns_number_gt                2759
_reflns_number_total             3074
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            b814448f.txt
_cod_data_source_block           rsrx55
_cod_original_sg_symbol_H-M      C2
_cod_database_code               7150533