Total synthesis of 2‴,5‴-diepisilvestrol and its c1‴ epimer: key structure activity relationships at c1‴ and c2‴.
Chambers, Jennifer M.; Huang, David C. S.; Lindqvist, Lisa M.; Savage, G. Paul; White, Jonathan M.; Rizzacasa, Mark A.; Journal of natural products 75 (2012) 1500–1504; doi:10.1021/np300376f

data_1508276
_publ_section_title
;
 Total synthesis of 2&#x2034;,5&#x2034;-diepisilvestrol and its c1&#x2034;
 epimer: key structure activity relationships at c1&#x2034; and
 c2&#x2034;.
;
_journal_issue                   8
_journal_name_full               'Journal of natural products'
_journal_page_first              1500
_journal_page_last               1504
_journal_paper_doi               10.1021/np300376f
_journal_volume                  75
_journal_year                    2012
_chemical_formula_sum            'C27 H50 O7 Si2'
_chemical_formula_weight         542.85
_chemical_name_systematic
;
 ?
;
_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            4
_cell_length_a                   8.2450(2)
_cell_length_b                   10.6777(3)
_cell_length_c                   36.1362(14)
_cell_measurement_reflns_used    4209
_cell_measurement_temperature    130.0
_cell_measurement_theta_max      76.8519
_cell_measurement_theta_min      3.6639
_cell_volume                     3181.35(17)
_computing_cell_refinement
;
CrysAlisPro, Agilent Technologies,
Version 1.171.34.49 (release 20-01-2011 CrysAlis171 .NET)
(compiled Jan 20 2011,15:58:25)
;
_computing_data_collection
;
CrysAlisPro, Agilent Technologies,
Version 1.171.34.49 (release 20-01-2011 CrysAlis171 .NET)
(compiled Jan 20 2011,15:58:25)
;
_computing_data_reduction
;
CrysAlisPro, Agilent Technologies,
Version 1.171.34.49 (release 20-01-2011 CrysAlis171 .NET)
(compiled Jan 20 2011,15:58:25)
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      130.0
_diffrn_measured_fraction_theta_full 0.987
_diffrn_measured_fraction_theta_max 0.987
_diffrn_measurement_device_type  'SuperNova, Dual, Cu at zero, Atlas'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_source         'SuperNova (Cu) X-ray Source'
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.5418
_diffrn_reflns_av_R_equivalents  0.0248
_diffrn_reflns_av_sigmaI/netI    0.0355
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       42
_diffrn_reflns_limit_l_min       -45
_diffrn_reflns_number            10320
_diffrn_reflns_theta_full        77.16
_diffrn_reflns_theta_max         77.16
_diffrn_reflns_theta_min         4.32
_exptl_absorpt_coefficient_mu    1.324
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.95116
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro, Agilent Technologies,
Version 1.171.34.49 (release 20-01-2011 CrysAlis171 .NET)
(compiled Jan 20 2011,15:58:25)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.133
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             1184
_exptl_crystal_size_max          0.3788
_exptl_crystal_size_mid          0.2549
_exptl_crystal_size_min          0.0426
_refine_diff_density_max         0.540
_refine_diff_density_min         -0.285
_refine_diff_density_rms         0.044
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.02(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.045
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     390
_refine_ls_number_reflns         5849
_refine_ls_number_restraints     21
_refine_ls_restrained_S_all      1.048
_refine_ls_R_factor_all          0.0480
_refine_ls_R_factor_gt           0.0436
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0698P)^2^+0.5296P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1165
_refine_ls_wR_factor_ref         0.1208
_reflns_number_gt                5388
_reflns_number_total             5849
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            np300376f_si_002.cif
_cod_data_source_block           shelxl
_cod_database_code               1508276