Total synthesis of the taraxacine A natural product <i>via</i> Ag(I)-catalysed imidate-alkyne cyclization.
Zalte, Rajesh R.; Festa, Alexey A.; Demidov, Sergei A.; Awuku, Samuel O.; Golubenkova, Alexandra S.; Mironov, Yuri Yu; Golantsov, Nikita E.; Storozhenko, Olga A.; Novikov, Anton P.; Voskressensky, Leonid G.; Organic & biomolecular chemistry 23 (2025) 1386–1393; doi:10.1039/d4ob01876a

data_7160297
_publ_section_title
;
 Total synthesis of the taraxacine A natural product <i>via</i>
 Ag(I)-catalysed imidate-alkyne cyclization.
;
_journal_issue                   6
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              1386
_journal_page_last               1393
_journal_paper_doi               10.1039/d4ob01876a
_journal_volume                  23
_journal_year                    2025
_chemical_formula_moiety         'C19 H16 N2 O'
_chemical_formula_sum            'C19 H16 N2 O'
_chemical_formula_weight         288.34
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     dual
_audit_creation_date             2024-09-13
_audit_creation_method
;
Olex2 1.5
(compiled 2024.02.16 svn.r378c4104 for OlexSys, GUI svn.r6928)
;
_audit_update_record
;
2024-11-14 deposited with the CCDC.	2024-12-16 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 92.558(4)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   15.7758(14)
_cell_length_b                   5.9637(6)
_cell_length_c                   15.5467(14)
_cell_measurement_reflns_used    2132
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      24.387
_cell_measurement_theta_min      2.584
_cell_volume                     1461.2(2)
_computing_cell_refinement       'SAINT V8.40B (Bruker, 2020)'
_computing_data_reduction        'SAINT V8.40B (Bruker, 2020)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2018/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type
'Bruker KAPPA APEX II area-detector diffractometer'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0819
_diffrn_reflns_av_unetI/netI     0.0646
_diffrn_reflns_Laue_measured_fraction_full 0.995
_diffrn_reflns_Laue_measured_fraction_max 0.996
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -20
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            20681
_diffrn_reflns_point_group_measured_fraction_full 0.995
_diffrn_reflns_point_group_measured_fraction_max 0.996
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.500
_diffrn_reflns_theta_min         4.286
_exptl_absorpt_coefficient_mu    0.082
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.9218
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.0688 before and 0.0610 after correction.
The Ratio of minimum to maximum transmission is 0.9218.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            yellow
_exptl_crystal_colour_primary    yellow
_exptl_crystal_density_diffrn    1.311
_exptl_crystal_description       block
_exptl_crystal_F_000             608
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.14
_refine_diff_density_max         0.266
_refine_diff_density_min         -0.227
_refine_diff_density_rms         0.053
_refine_ls_extinction_coef       0.0067(10)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2018/3 (Sheldrick 2018)'
_refine_ls_goodness_of_fit_ref   1.029
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     264
_refine_ls_number_reflns         3347
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.029
_refine_ls_R_factor_all          0.0942
_refine_ls_R_factor_gt           0.0476
_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^)+(0.0364P)^2^+0.3927P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0894
_refine_ls_wR_factor_ref         0.1083
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2133
_reflns_number_total             3347
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d4ob01876a2.cif
_cod_data_source_block           lk5950_lt_0ma
_cod_depositor_comments          'Adding full bibliography for 7160297.cif.'
_cod_database_code               7160297
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_max   0.989
_shelx_estimated_absorpt_t_min   0.980
_olex2_refinement_description
;
;
_shelx_res_checksum              92502
_olex2_submission_special_instructions 'No special instructions were received'