Synthetic Progress toward Azadirachtins. 1. Enantio- and Diastereoselective Synthesis of the Left-Wing Fragment of 11-epi-Azadirachtin I.
Shi, Hang; Tan, Ceheng; Zhang, Weibin; Zhang, Zichun; Long, Rong; Luo, Tuoping; Yang, Zhen; Organic letters 17 (2015) 2342–2345; doi:10.1021/acs.orglett.5b00829

data_1520756
_publ_section_title
;
 Synthetic Progress toward Azadirachtins. 1. Enantio- and
 Diastereoselective Synthesis of the Left-Wing Fragment of
 11-epi-Azadirachtin I.
;
_journal_issue                   10
_journal_name_full               'Organic letters'
_journal_page_first              2342
_journal_page_last               2345
_journal_paper_doi               10.1021/acs.orglett.5b00829
_journal_volume                  17
_journal_year                    2015
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C28 H44 O4 Si2'
_chemical_formula_sum            'C28 H44 O4 Si2'
_chemical_formula_weight         500.81
_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                   7.70200(10)
_cell_length_b                   13.1321(2)
_cell_length_c                   27.4999(19)
_cell_measurement_reflns_used    20493
_cell_measurement_temperature    113(2)
_cell_measurement_theta_max      68.20
_cell_measurement_theta_min      6.60
_cell_volume                     2781.4(2)
_computing_cell_refinement       'CrystalClear-SM Auto 2.0 r4'
_computing_data_collection       'CrystalClear-SM Auto 2.0 r4 (Rigaku, 2009)'
_computing_data_reduction        'CrystalClear-SM Auto 2.0 r4'
_computing_molecular_graphics    'CrystalStructure 4.0'
_computing_publication_material  'CrystalStructure 4.0 (Rigaku, 2009)'
_computing_structure_refinement  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      113(2)
_diffrn_measured_fraction_theta_full 0.983
_diffrn_measured_fraction_theta_max 0.983
_diffrn_measurement_device_type  'Rigaku Saturn944+ CCD'
_diffrn_measurement_method       \w
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0436
_diffrn_reflns_av_sigmaI/netI    0.0404
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       32
_diffrn_reflns_limit_l_min       -32
_diffrn_reflns_number            21439
_diffrn_reflns_theta_full        68.23
_diffrn_reflns_theta_max         68.23
_diffrn_reflns_theta_min         6.59
_exptl_absorpt_coefficient_mu    1.395
_exptl_absorpt_correction_T_max  0.837
_exptl_absorpt_correction_T_min  0.651
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Jacobson, R. (1998) Private communication'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.196
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             1088
_exptl_crystal_size_max          0.20
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.258
_refine_diff_density_min         -0.321
_refine_diff_density_rms         0.073
_refine_ls_abs_structure_details
'Flack H D (1983), Acta Cryst. A39, 876-881. 2117 Friedel Pairs'
_refine_ls_abs_structure_Flack   0.02(2)
_refine_ls_extinction_coef       0.0028(2)
_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   1.143
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     317
_refine_ls_number_reflns         4975
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.144
_refine_ls_R_factor_all          0.0375
_refine_ls_R_factor_gt           0.0326
_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^)+(0.0257P)^2^+1.2922P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0727
_refine_ls_wR_factor_ref         0.0861
_reflns_number_gt                4681
_reflns_number_total             4975
_reflns_threshold_expression     >2\s(I)
_cod_data_source_file            ol5b00829_si_001.cif
_cod_data_source_block           b
_cod_database_code               1520756