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_7159439
_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_formula_sum            'C23 H15 N O'
_chemical_formula_weight         321.36
_space_group_crystal_system      orthorhombic
_space_group_IT_number           29
_space_group_name_Hall           'P 2c -2ac'
_space_group_name_H-M_alt        'P c a 21'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2018/3
_audit_update_record
;
2023-05-18 deposited with the CCDC.	2023-06-20 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   22.3743(7)
_cell_length_b                   5.3342(2)
_cell_length_c                   13.0665(4)
_cell_measurement_reflns_used    8056
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      28.20
_cell_measurement_theta_min      2.40
_cell_volume                     1559.47(9)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2018/3 (Sheldrick, 2018)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0505
_diffrn_reflns_av_unetI/netI     0.0324
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       29
_diffrn_reflns_limit_h_min       -26
_diffrn_reflns_limit_k_max       7
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -17
_diffrn_reflns_number            24697
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.000
_diffrn_reflns_theta_max         28.328
_diffrn_reflns_theta_min         2.397
_diffrn_source                   'fine-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.084
_exptl_absorpt_correction_type   none
_exptl_absorpt_process_details   'SADABS 2.05 (Sheldrick, 2002)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.369
_exptl_crystal_description       block
_exptl_crystal_F_000             672
_exptl_crystal_size_max          0.240
_exptl_crystal_size_mid          0.160
_exptl_crystal_size_min          0.120
_refine_diff_density_max         0.535
_refine_diff_density_min         -0.259
_refine_diff_density_rms         0.044
_refine_ls_abs_structure_details
;
 Flack x determined using 1447 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   1.0(6)
_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     226
_refine_ls_number_reflns         3884
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.048
_refine_ls_R_factor_all          0.0520
_refine_ls_R_factor_gt           0.0433
_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^)+(0.0453P)^2^+0.6188P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1005
_refine_ls_wR_factor_ref         0.1050
_reflns_Friedel_coverage         0.914
_reflns_Friedel_fraction_full    0.999
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                3436
_reflns_number_total             3884
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d3ob00804e3.cif
_cod_data_source_block           shelx
_cod_depositor_comments
'Adding full bibliography for 7159438--7159439.cif.'
_cod_database_code               7159439
_shelx_shelxl_version_number     2018/3
_shelx_estimated_absorpt_t_min   0.980
_shelx_estimated_absorpt_t_max   0.990
_shelx_res_checksum              60428