An efficient route to highly strained cyclobutenes: indium-catalyzed reactions of enynals with alkynes.
Liang, Renxiao; Jiang, Huanfeng; Zhu, Shifa; Chemical communications (Cambridge, England) 51 (2015) 5530–5533; doi:10.1039/c4cc08506j

data_7116306
_publ_section_title
;
 An efficient route to highly strained cyclobutenes: indium-catalyzed
 reactions of enynals with alkynes.
;
_journal_issue                   25
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              5530
_journal_page_last               5533
_journal_paper_doi               10.1039/c4cc08506j
_journal_volume                  51
_journal_year                    2015
_chemical_formula_sum            'C25 H18 O3'
_chemical_formula_weight         366.39
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_audit_update_record
;
2014-10-25 deposited with the CCDC.
2015-01-05 downloaded from the CCDC.
;
_cell_angle_alpha                90.00
_cell_angle_beta                 94.2110(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   11.12900(10)
_cell_length_b                   10.01500(10)
_cell_length_c                   16.4841(2)
_cell_measurement_temperature    293(2)
_cell_volume                     1832.31(3)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0269
_diffrn_reflns_av_sigmaI/netI    0.0147
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            20325
_diffrn_reflns_theta_full        73.61
_diffrn_reflns_theta_max         73.61
_diffrn_reflns_theta_min         3.98
_exptl_absorpt_coefficient_mu    0.692
_exptl_crystal_density_diffrn    1.328
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             768
_refine_diff_density_max         0.246
_refine_diff_density_min         -0.221
_refine_diff_density_rms         0.048
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.060
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     254
_refine_ls_number_reflns         3686
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.060
_refine_ls_R_factor_all          0.0400
_refine_ls_R_factor_gt           0.0366
_refine_ls_shift/su_max          0.004
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0559P)^2^+0.4120P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0960
_refine_ls_wR_factor_ref         0.0995
_reflns_number_gt                3346
_reflns_number_total             3686
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c4cc08506j2.cif
_cod_data_source_block           exp_1136
_cod_depositor_comments          'Adding full bibliography for 7116306.cif.'
_cod_original_sg_symbol_H-M      'P 21/c'
_cod_database_code               7116306