Asymmetric total synthesis of an iboga-type indole alkaloid, voacangalactone, newly isolated from Voacanga africana.
Harada, Masaya; Asaba, Ken Nunettsu; Iwai, Masumi; Kogure, Noriyuki; Kitajima, Mariko; Takayama, Hiromitsu; Organic letters 14 (2012) 5800–5803; doi:10.1021/ol3027945

data_1508764
_publ_section_title
;
 Asymmetric total synthesis of an iboga-type indole alkaloid,
 voacangalactone, newly isolated from Voacanga africana.
;
_journal_issue                   22
_journal_name_full               'Organic letters'
_journal_page_first              5800
_journal_page_last               5803
_journal_paper_doi               10.1021/ol3027945
_journal_volume                  14
_journal_year                    2012
_chemical_absolute_configuration rm
_chemical_formula_sum            'C34 H45 N O7 Si'
_chemical_formula_weight         607.80
_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                 112.285(5)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   25.936(10)
_cell_length_b                   11.367(4)
_cell_length_c                   12.416(5)
_cell_measurement_reflns_used    147
_cell_measurement_temperature    173
_cell_measurement_theta_max      12.49
_cell_measurement_theta_min      3.07
_cell_volume                     3387(2)
_computing_cell_refinement       'APEX2 (Bruker AXS, 2006)'
_computing_data_collection       'APEX2 (Bruker AXS, 2006)'
_computing_data_reduction        'SAINT (Bruker AXS, 2004)'
_computing_molecular_graphics    'XSHEL (Bruker AXS,2002)'
_computing_publication_material  'XCIF (Bruker AXS, 2001)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      173
_diffrn_detector_area_resol_mean 8.333
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.974
_diffrn_measurement_device_type  'Bruker APEXII 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  0.2030
_diffrn_reflns_av_sigmaI/netI    0.4123
_diffrn_reflns_limit_h_max       30
_diffrn_reflns_limit_h_min       -33
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       13
_diffrn_reflns_limit_l_min       -16
_diffrn_reflns_number            9669
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         27.56
_diffrn_reflns_theta_min         1.70
_exptl_absorpt_coefficient_mu    0.115
_exptl_absorpt_correction_T_max  0.9886
_exptl_absorpt_correction_T_min  0.9886
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details
;
SADABS Sheldrick 1996
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.192
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             1304
_exptl_crystal_size_max          0.10
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.416
_refine_diff_density_min         -0.521
_refine_diff_density_rms         0.143
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.6(6)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.904
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     396
_refine_ls_number_reflns         5287
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.904
_refine_ls_R_factor_all          0.3213
_refine_ls_R_factor_gt           0.0879
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1075P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1731
_refine_ls_wR_factor_ref         0.3010
_reflns_number_gt                1583
_reflns_number_total             5287
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol3027945_si_002.cif
_cod_data_source_block           comp6revised
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
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 1891 2012-01-12 08:04:46Z andrius 
;
_cod_original_sg_symbol_H-M      'C2   '
_cod_database_code               1508764