Catalyst-Free Synthesis of 2,3-Dihydrobenzofurans via a Formal [4+1] Annulation of Propargylamines with Sulfur Ylides.
He, Xinwei; Xie, Mengqing; Tang, Qiang; Zuo, Youpeng; Li, Ruxue; Shang, Yongjia; The Journal of organic chemistry 84 (2019) 11623–11638; doi:10.1021/acs.joc.9b01557

data_4034512
_publ_section_title
;
 Catalyst-Free Synthesis of 2,3-Dihydrobenzofurans via a Formal [4+1]
 Annulation of Propargylamines with Sulfur Ylides.
;
_journal_issue                   18
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              11623
_journal_page_last               11638
_journal_paper_doi               10.1021/acs.joc.9b01557
_journal_volume                  84
_journal_year                    2019
_chemical_formula_sum            'C24 H18 O2'
_chemical_formula_weight         338.38
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2018/1
_cell_angle_alpha                90
_cell_angle_beta                 96.629(3)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   12.0583(11)
_cell_length_b                   7.5080(7)
_cell_length_c                   20.4002(17)
_cell_measurement_reflns_used    9054
_cell_measurement_temperature    273(2)
_cell_measurement_theta_max      27.50
_cell_measurement_theta_min      2.89
_cell_volume                     1834.6(3)
_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-2018/1 (Sheldrick, 2018)'
_diffrn_ambient_temperature      273(2)
_diffrn_measured_fraction_theta_full 0.980
_diffrn_measured_fraction_theta_max 0.962
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0287
_diffrn_reflns_av_unetI/netI     0.0147
_diffrn_reflns_Laue_measured_fraction_full 0.980
_diffrn_reflns_Laue_measured_fraction_max 0.962
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       26
_diffrn_reflns_limit_l_min       -26
_diffrn_reflns_number            59330
_diffrn_reflns_point_group_measured_fraction_full 0.980
_diffrn_reflns_point_group_measured_fraction_max 0.962
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         27.538
_diffrn_reflns_theta_min         2.893
_exptl_absorpt_coefficient_mu    0.077
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.225
_exptl_crystal_description       block
_exptl_crystal_F_000             712
_exptl_crystal_size_max          0.230
_exptl_crystal_size_mid          0.210
_exptl_crystal_size_min          0.200
_refine_diff_density_max         0.256
_refine_diff_density_min         -0.182
_refine_diff_density_rms         0.035
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.026
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     236
_refine_ls_number_reflns         4072
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.026
_refine_ls_R_factor_all          0.0693
_refine_ls_R_factor_gt           0.0626
_refine_ls_shift/su_max          0.048
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1000P)^2^+0.8580P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1823
_refine_ls_wR_factor_ref         0.1894
_reflns_Friedel_coverage         0.000
_reflns_number_gt                3644
_reflns_number_total             4072
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo9b01557_si_002.cif
_cod_data_source_block           180722e_0m
_cod_original_sg_symbol_H-M      'P 21/n'
_cod_database_code               4034512
_shelx_shelxl_version_number     2018/1
_shelx_estimated_absorpt_t_min   0.983
_shelx_estimated_absorpt_t_max   0.985
_shelx_res_checksum              2600
_shelx_hkl_checksum              14711