A reusable polymer anchored pyridine mediated formal [4 + 1] annulation reaction for the diastereoselective synthesis of 2,3-dihydrobenzofurans.
Kumari, Akanksha; Jain, Anshul; Shukla, Khyati; Patra, Ranjan; Rana, Nirmal K.; Organic & biomolecular chemistry 21 (2023) 5542–5546; doi:10.1039/d3ob00804e

data_7159438
_publ_section_title
;
 A reusable polymer anchored pyridine mediated formal [4 + 1] annulation
 reaction for the diastereoselective synthesis of 2,3-dihydrobenzofurans.
;
_journal_issue                   27
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              5542
_journal_page_last               5546
_journal_paper_doi               10.1039/d3ob00804e
_journal_volume                  21
_journal_year                    2023
_chemical_absolute_configuration rm
_chemical_formula_sum            'C23 H16 I2 O3'
_chemical_formula_weight         594.16
_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
_audit_creation_method           SHELXL-2018/3
_audit_update_record
;
2022-08-04 deposited with the CCDC.	2023-06-20 downloaded from the CCDC.
;
_cell_angle_alpha                90
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_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   8.1476(5)
_cell_length_b                   9.0775(6)
_cell_length_c                   27.2326(17)
_cell_measurement_reflns_used    9488
_cell_measurement_temperature    273(2)
_cell_measurement_theta_max      28.37
_cell_measurement_theta_min      2.36
_cell_volume                     2014.1(2)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX'
_computing_data_reduction        'Bruker SAINT'
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_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Bruker SMART APEX'
_diffrn_measurement_method       \w
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0485
_diffrn_reflns_av_unetI/netI     0.0295
_diffrn_reflns_Laue_measured_fraction_full 0.998
_diffrn_reflns_Laue_measured_fraction_max 0.998
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
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_diffrn_reflns_limit_l_min       -36
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_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.997
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.361
_diffrn_reflns_theta_min         2.913
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    3.144
_exptl_absorpt_correction_T_max  0.9425
_exptl_absorpt_correction_T_min  0.8402
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS 2.05 (Sheldrick, 2002)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.959
_exptl_crystal_description       block
_exptl_crystal_F_000             1136
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_refine_diff_density_max         0.423
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_refine_ls_abs_structure_details
;
 Refined as an inversion twin.
;
_refine_ls_abs_structure_Flack   0.44(2)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.056
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
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_refine_ls_number_reflns         5019
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.056
_refine_ls_R_factor_all          0.0216
_refine_ls_R_factor_gt           0.0190
_refine_ls_shift/su_max          0.004
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+1.4157P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0389
_refine_ls_wR_factor_ref         0.0403
_reflns_Friedel_coverage         0.746
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                4756
_reflns_number_total             5019
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d3ob00804e2.cif
_cod_data_source_block           shelx
_cod_depositor_comments
'Adding full bibliography for 7159438--7159439.cif.'
_cod_database_code               7159438
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_min   0.452
_shelx_estimated_absorpt_t_max   0.744
_exptl_absorpt_special_details
; 
 ? 
;
_shelx_res_checksum              2755