Synthesis of the A-D Ring System of the Gambieric Acids.
Clark, J. Stephen; Romiti, Filippo; Sieng, Bora; Paterson, Laura C.; Stewart, Alister; Chaudhury, Subhabrata; Thomas, Lynne H.; Organic letters 17 (2015) 4694–4697; doi:10.1021/acs.orglett.5b02093

data_1555233
_publ_section_title
;
 Synthesis of the A-D Ring System of the Gambieric Acids.
;
_journal_issue                   19
_journal_name_full               'Organic letters'
_journal_page_first              4694
_journal_page_last               4697
_journal_paper_doi               10.1021/acs.orglett.5b02093
_journal_volume                  17
_journal_year                    2015
_chemical_absolute_configuration unk
_chemical_formula_sum            'C22 H36 O6 Si'
_chemical_formula_weight         424.60
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     difmap
_audit_creation_method           SHELXL-2014/7
_cell_angle_alpha                90
_cell_angle_beta                 111.164(5)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   6.3950(7)
_cell_length_b                   46.881(6)
_cell_length_c                   8.2621(10)
_cell_measurement_temperature    100(2)
_cell_volume                     2309.9(5)
_computing_cell_refinement       'Bruker APEX2 (2009)'
_computing_data_collection       'Bruker APEX2 (2009)'
_computing_data_reduction        'Bruker APEX2 (2009)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS (Sheldrick, 2014)'
_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       'CCD; rotation images'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0675
_diffrn_reflns_av_unetI/netI     0.0469
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       5
_diffrn_reflns_limit_h_min       -5
_diffrn_reflns_limit_k_max       42
_diffrn_reflns_limit_k_min       -42
_diffrn_reflns_limit_l_max       7
_diffrn_reflns_limit_l_min       -7
_diffrn_reflns_number            21847
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        18.848
_diffrn_reflns_theta_max         18.848
_diffrn_reflns_theta_min         1.738
_exptl_absorpt_coefficient_mu    0.135
_exptl_absorpt_correction_T_max  0.7444
_exptl_absorpt_correction_T_min  0.5826
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Blessing, 1997)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.221
_exptl_crystal_description       block
_exptl_crystal_F_000             920
_exptl_crystal_size_max          0.1
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.790
_refine_diff_density_min         -0.323
_refine_diff_density_rms         0.096
_refine_ls_abs_structure_details
;
 Flack x determined using 1445 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.22(10)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.094
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     495
_refine_ls_number_reflns         3628
_refine_ls_number_restraints     1015
_refine_ls_restrained_S_all      0.979
_refine_ls_R_factor_all          0.0857
_refine_ls_R_factor_gt           0.0779
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1389P)^2^+6.5047P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2029
_refine_ls_wR_factor_ref         0.2101
_reflns_Friedel_coverage         0.964
_reflns_Friedel_fraction_full    0.997
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                3293
_reflns_number_total             3628
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ol5b02093_si_001.cif
_cod_data_source_block           shelx
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               1555233
_shelx_shelxl_version_number     2014/7
_shelx_res_checksum              10962
_shelx_hkl_checksum              91467