Convergent Route to ent-Kaurane Diterpenoids: Total Synthesis of Lungshengenin D and 1α,6α-Diacetoxy-ent-kaura-9(11),16-dien-12,15-dione.
Zhao, Xiangbo; Li, Wu; Wang, Junjie; Ma, Dawei; Journal of the American Chemical Society 139 (2017) 2932–2935; doi:10.1021/jacs.7b00140

data_4125664
_publ_section_title
;
 Convergent Route to ent-Kaurane Diterpenoids: Total Synthesis of
 Lungshengenin D and
 1\a,6\a-Diacetoxy-ent-kaura-9(11),16-dien-12,15-dione.
;
_journal_issue                   8
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              2932
_journal_page_last               2935
_journal_paper_doi               10.1021/jacs.7b00140
_journal_volume                  139
_journal_year                    2017
_chemical_absolute_configuration unk
_chemical_formula_sum            'C20 H24 O4'
_chemical_formula_weight         328.39
_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'
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2013
_cell_angle_alpha                90
_cell_angle_beta                 109.494(4)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   6.1968(11)
_cell_length_b                   17.198(3)
_cell_length_c                   8.2164(15)
_cell_measurement_reflns_used    1581
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      52.634
_cell_measurement_theta_min      4.737
_cell_volume                     825.4(3)
_computing_cell_refinement       'Bruker SMART'
_computing_data_collection       'Bruker SMART'
_computing_data_reduction        'Bruker SHELXTL'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_computing_structure_solution    'Bruker SHELXTL'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0299
_diffrn_reflns_av_unetI/netI     0.0435
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -5
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -21
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            4967
_diffrn_reflns_point_group_measured_fraction_full 0.871
_diffrn_reflns_point_group_measured_fraction_max 0.865
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.999
_diffrn_reflns_theta_min         2.368
_exptl_absorpt_coefficient_mu    0.091
_exptl_absorpt_correction_T_max  0.7456
_exptl_absorpt_correction_T_min  0.5948
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.321
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             352
_exptl_crystal_size_max          0.200
_exptl_crystal_size_mid          0.170
_exptl_crystal_size_min          0.130
_refine_diff_density_max         0.207
_refine_diff_density_min         -0.178
_refine_diff_density_rms         0.035
_refine_ls_abs_structure_details
; 
 Flack x determined using 912 quotients [(I+)-(I-)]/[(I+)+(I-)] 
 (Parsons and Flack (2004), Acta Cryst. A60, s61). 
;
_refine_ls_abs_structure_Flack   0.1(9)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.048
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     221
_refine_ls_number_reflns         2823
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.048
_refine_ls_R_factor_all          0.0515
_refine_ls_R_factor_gt           0.0462
_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^)+(0.0581P)^2^+0.0879P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1108
_refine_ls_wR_factor_ref         0.1151
_reflns_Friedel_coverage         0.672
_reflns_Friedel_fraction_full    0.734
_reflns_Friedel_fraction_max     0.721
_reflns_number_gt                2548
_reflns_number_total             2823
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja7b00140_si_006.cif
_cod_data_source_block           cd16206
_cod_original_cell_volume        825.5(3)
_cod_database_code               4125664
_shelx_estimated_absorpt_t_min   0.982
_shelx_estimated_absorpt_t_max   0.988
_shelxl_version_number           2013-4
_shelx_res_checksum              64827
_shelx_hkl_checksum              78607