The Landscape of Lankacidin Biomimetic Synthesis: Structural Revisions and Biogenetic Implications.
Zheng, Kuan; Shen, Defeng; Zhang, Bingbing; Hong, Ran; The Journal of organic chemistry  (2020) –; doi:10.1021/acs.joc.0c01930

data_4038904
_publ_section_title
;
 The Landscape of Lankacidin Biomimetic Synthesis: Structural Revisions
 and Biogenetic Implications.
;
_journal_name_full               'The Journal of organic chemistry'
_journal_paper_doi               10.1021/acs.joc.0c01930
_journal_year                    2020
_chemical_absolute_configuration rmad
_chemical_formula_moiety         'C49 H69 N O8 Si2'
_chemical_formula_sum            'C49 H69 N O8 Si2'
_chemical_formula_weight         856.23
_space_group_crystal_system      orthorhombic
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2017-12-12
_audit_creation_method
;
Olex2 1.2
(compiled 2017.03.28 svn.r3405 for OlexSys, GUI svn.r5337)
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   10.1898(17)
_cell_length_b                   20.428(3)
_cell_length_c                   24.565(4)
_cell_measurement_reflns_used    7426
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      20.52
_cell_measurement_theta_min      2.16
_cell_volume                     5113.4(14)
_computing_cell_refinement       'SAINT v7.68A (Bruker, 2009)'
_computing_data_reduction        'SAINT v7.68A (Bruker, 2009)'
_computing_molecular_graphics    'Olex2 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'ShelXL (Sheldrick, 2015)'
_computing_structure_solution    'ShelXT (Sheldrick, 2015)'
_diffrn_ambient_temperature      296.15
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0452
_diffrn_reflns_av_unetI/netI     0.0487
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -26
_diffrn_reflns_limit_l_max       31
_diffrn_reflns_limit_l_min       -31
_diffrn_reflns_number            42144
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.999
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.501
_diffrn_reflns_theta_min         1.658
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.118
_exptl_absorpt_correction_T_max  0.7456
_exptl_absorpt_correction_T_min  0.6640
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
'SADABS-2008/1 (Bruker,2008) was used for absorption correction. wR2(int) was 0.0853 before and 0.0463 after correction. The Ratio of minimum to maximum transmission is 0.8906. The \l/2 correction factor is 0.0015.'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.112
_exptl_crystal_description       block
_exptl_crystal_F_000             1848
_exptl_crystal_size_max          0.2
_exptl_crystal_size_mid          0.15
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.392
_refine_diff_density_min         -0.335
_refine_diff_density_rms         0.040
_refine_ls_abs_structure_details
;
 Flack x determined using 2294 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.03(4)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.015
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     555
_refine_ls_number_reflns         11753
_refine_ls_number_restraints     36
_refine_ls_restrained_S_all      1.062
_refine_ls_R_factor_all          0.1108
_refine_ls_R_factor_gt           0.0615
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0923P)^2^+0.6264P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1546
_refine_ls_wR_factor_ref         0.1810
_reflns_Friedel_coverage         0.809
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.998
_reflns_number_gt                7038
_reflns_number_total             11753
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo0c01930_si_001.cif
_cod_data_source_block           mo_dm17460_0m
_cod_database_code               4038904
_shelx_shelxl_version_number     2017/1
_shelx_estimated_absorpt_t_max   0.991
_shelx_estimated_absorpt_t_min   0.977
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups, All N(H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2. Uiso/Uaniso restraints and constraints
Si2 \\sim C28 \\sim C29 \\sim C30 \\sim C31 \\sim C32 \\sim C33: within 2A with
sigma of 0.01 and sigma for terminal atoms of 0.02
3.a Ternary CH refined with riding coordinates:
 C1(H1A), C4(H4), C5(H5), C8(H8), C14(H14), C26(H26)
3.b Secondary CH2 refined with riding coordinates:
 C7(H7A,H7B), C13(H13A,H13B)
3.c Aromatic/amide H refined with riding coordinates:
 N1(H1), C9(H9), C10(H10), C12(H12), C15(H15), C16(H16), C18(H18), C39(H39),
 C40(H40), C41(H41), C42(H42), C43(H43), C45(H45), C46(H46), C47(H47), C48(H48),
  C49(H49)
3.d Idealised Me refined as rotating group:
 C19(H19A,H19B,H19C), C20(H20A,H20B,H20C), C21(H21A,H21B,H21C), C22(H22A,H22B,
 H22C), C24(H24A,H24B,H24C), C27(H27A,H27B,H27C), C28(H28A,H28B,H28C), C29(H29A,
 H29B,H29C), C31(H31A,H31B,H31C), C32(H32A,H32B,H32C), C33(H33A,H33B,H33C),
 C35(H35A,H35B,H35C), C36(H36A,H36B,H36C), C37(H37A,H37B,H37C)
;
_shelx_res_checksum              2332
_shelx_hkl_checksum              53079
_olex2_submission_special_instructions 'No special instructions were received'