A concise approach to a gelsemine core structure using an oxygen to carbon bridge swapping strategy.
Tchabanenko, Kirill; Simpkins, Nigel S.; Male, Louise; Organic letters 10 (2008) 4747–4750; doi:10.1021/ol801835q

data_1504905
_publ_section_title
;
 A concise approach to a gelsemine core structure using an oxygen to
 carbon bridge swapping strategy.
;
_journal_issue                   21
_journal_name_full               'Organic letters'
_journal_page_first              4747
_journal_page_last               4750
_journal_paper_doi               10.1021/ol801835q
_journal_volume                  10
_journal_year                    2008
_chemical_formula_moiety         'C19 H32 N2 O5 Si2'
_chemical_formula_sum            'C19 H32 N2 O5 Si2'
_chemical_formula_weight         424.65
_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                 92.689(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   15.8689(8)
_cell_length_b                   6.8068(3)
_cell_length_c                   21.1152(8)
_cell_measurement_reflns_used    33400
_cell_measurement_temperature    120(2)
_cell_measurement_theta_max      27.48
_cell_measurement_theta_min      2.91
_cell_volume                     2278.28(18)
_computing_cell_refinement
'DENZO (Otwinowski & Minor, 1997) & COLLECT (Hooft, R.W.W., 1998)'
_computing_data_collection       'COLLECT (Hooft, R.W.W., 1998)'
_computing_data_reduction
'DENZO (Otwinowski & Minor, 1997) & COLLECT (Hooft, R.W.W., 1998)'
_computing_molecular_graphics
;
PLATON/PLUTON (Spek, A. L., 1998)& 
ORTEP3 for Windows (Farrugia, L. J., 1997)
;
_computing_publication_material  'WinGX (Farrugia, 1999)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997'
_diffrn_ambient_temperature      120(2)
_diffrn_detector_area_resol_mean '4096x4096pixels / 62x62mm'
_diffrn_measured_fraction_theta_full 0.992
_diffrn_measured_fraction_theta_max 0.992
_diffrn_measurement_device_type
'Bruker-Nonius APEX II CCD camera on \k-goniostat'
_diffrn_measurement_method       '\f & \w scans'
_diffrn_radiation_monochromator  '10cm confocal mirrors'
_diffrn_radiation_source         'Bruker-Nonius FR591 rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0738
_diffrn_reflns_av_sigmaI/netI    0.0759
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -19
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            19565
_diffrn_reflns_theta_full        27.48
_diffrn_reflns_theta_max         27.48
_diffrn_reflns_theta_min         3.14
_exptl_absorpt_coefficient_mu    0.186
_exptl_absorpt_correction_T_max  0.9963
_exptl_absorpt_correction_T_min  0.9816
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS 2007/2 (Sheldrick, G.M., 2007)'
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.238
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Plate
_exptl_crystal_F_000             912
_exptl_crystal_size_max          0.10
_exptl_crystal_size_mid          0.07
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.415
_refine_diff_density_min         -0.431
_refine_diff_density_rms         0.081
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.112
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     261
_refine_ls_number_reflns         5184
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.112
_refine_ls_R_factor_all          0.1233
_refine_ls_R_factor_gt           0.0723
_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^)+(0.0000P)^2^+5.9026P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1263
_refine_ls_wR_factor_ref         0.1517
_reflns_number_gt                3495
_reflns_number_total             5184
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol801835q_si_002.cif
_cod_data_source_block           12
_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 2.4.1 from
2010-06-29.

'_exptl_absorpt_correction_type' value 'Multi-scan'
changed to 'multi-scan' 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 2(1)/c'
_cod_database_code               1504905