Lewis acid-promoted intramolecular cyclization of ortho-prenylated chalcones: application to first total synthesis of (±) involucrasin C and its novel analogues
Ahamad, Jarish; Khatua, Rashmi Ranjan; Khan, Faiz Ahmed; RSC Advances 15 (2025) 27254–27259; doi:10.1039/D5RA04830C

data_7250751
_publ_section_title
;
 Lewis acid-promoted intramolecular cyclization of ortho-prenylated
 chalcones: application to first total synthesis of (+-) involucrasin C
 and its novel analogues
;
_journal_issue                   33
_journal_name_full               'RSC Advances'
_journal_page_first              27254
_journal_page_last               27259
_journal_paper_doi               10.1039/D5RA04830C
_journal_volume                  15
_journal_year                    2025
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C24 H22 O2'
_chemical_formula_sum            'C24 H22 O2'
_chemical_formula_weight         342.41
_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             2024-08-08
_audit_creation_method
;
Olex2 1.5-alpha
(compiled 2024.02.16 svn.r378c4104 for OlexSys, GUI svn.r6928)
;
_audit_update_record
;
2024-08-08 deposited with the CCDC.	2025-07-18 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.9481(8)
_cell_length_b                   12.8917(16)
_cell_length_c                   17.710(2)
_cell_measurement_reflns_used    3589
_cell_measurement_temperature    298
_cell_measurement_theta_max      21.759
_cell_measurement_theta_min      2.300
_cell_volume                     1814.6(4)
_computing_cell_refinement       'SAINT V8.40B (?, 2016)'
_computing_data_reduction        'SAINT V8.40B (?, 2016)'
_computing_molecular_graphics    'Olex2 1.5-alpha (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5-alpha (Dolomanov et al., 2009)'
_computing_structure_refinement  'XL  (Sheldrick, 2008)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_temperature      298
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  'Bruker APEX-IV Photon II'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0810
_diffrn_reflns_av_unetI/netI     0.0567
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.997
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       16
_diffrn_reflns_limit_k_min       -16
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            23651
_diffrn_reflns_point_group_measured_fraction_full 1.000
_diffrn_reflns_point_group_measured_fraction_max 0.997
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.124
_diffrn_reflns_theta_min         2.300
_diffrn_source_current           1.4
_diffrn_source_power             0.07
_diffrn_source_voltage           50.0
_exptl_absorpt_coefficient_mu    0.078
_exptl_absorpt_correction_T_max  0.7455
_exptl_absorpt_correction_T_min  0.5383
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
SADABS-2016/2 (Bruker,2016/2) was used for absorption correction.
wR2(int) was 0.1103 before and 0.0670 after correction.
The Ratio of minimum to maximum transmission is 0.7221.
The \l/2 correction factor is Not present.
;
_exptl_crystal_colour            'clear light colourless'
_exptl_crystal_colour_lustre     clear
_exptl_crystal_colour_modifier   light
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.253
_exptl_crystal_description       needle
_exptl_crystal_F_000             728
_exptl_crystal_size_max          0.659
_exptl_crystal_size_mid          0.049
_exptl_crystal_size_min          0.025
_refine_diff_density_max         0.125
_refine_diff_density_min         -0.122
_refine_diff_density_rms         0.031
_refine_ls_abs_structure_details
;
 Refined as an inversion twin.
;
_refine_ls_abs_structure_Flack   0(2)
_refine_ls_extinction_coef       0.015(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2019/1 (Sheldrick 2019)'
_refine_ls_goodness_of_fit_ref   1.051
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     238
_refine_ls_number_reflns         4006
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.051
_refine_ls_R_factor_all          0.0902
_refine_ls_R_factor_gt           0.0452
_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^)+(0.0358P)^2^+0.1309P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0864
_refine_ls_wR_factor_ref         0.1033
_reflns_Friedel_coverage         0.744
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.996
_reflns_number_gt                2663
_reflns_number_total             4006
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5ra04830c2.cif
_cod_data_source_block           mo_fak_ja_801
_cod_original_cell_volume        1814.7(4)
_cod_database_code               7250751
_shelx_shelxl_version_number     2019/1
_shelx_estimated_absorpt_t_max   0.998
_shelx_estimated_absorpt_t_min   0.950
_olex2_refinement_description
;
1. Twinned data refinement
 Scales: 1(2)
 0(2)
2. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All O(H) groups
3.a Ternary CH refined with riding coordinates:
 C009(H009), C17(H17), C16(H16)
3.b Secondary CH2 refined with riding coordinates:
 C8(H8A,H8B), C15(H15A,H15B)
3.c Aromatic/amide H refined with riding coordinates:
 C12(H12), C9(H9), C10(H10), C23(H23), C11(H11), C19(H19), C20(H20), C1(H1),
 C5(H5), C2(H2A), C3(H3), C21(H21), C4(H4), C22(H22)
3.d Idealised tetrahedral OH refined as rotating group:
 O2(H2)
;
_shelx_res_checksum              82528
_shelx_hkl_checksum              2672
_olex2_exptl_crystal_mounting_method 'Nylon loop used'
_olex2_submission_special_instructions 'No special instructions were received'