Catalytic Enantioselective Synthesis of Cyclobutenes from Alkynes and Alkenyl Derivatives.
Parsutkar, Mahesh M.; Pagar, Vinayak Vishnu; RajanBabu, T. V.; Journal of the American Chemical Society 141 (2019) 15367–15377; doi:10.1021/jacs.9b07885

data_4128962
_publ_section_title
;
 Catalytic Enantioselective Synthesis of Cyclobutenes from Alkynes and
 Alkenyl Derivatives.
;
_journal_issue                   38
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              15367
_journal_page_last               15377
_journal_paper_doi               10.1021/jacs.9b07885
_journal_volume                  141
_journal_year                    2019
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C24 H24 Br2 O2'
_chemical_formula_sum            'C24 H24 Br2 O2'
_chemical_formula_weight         504.25
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      4
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_conform_dict_location     ftp://ftp.iucr.org/pub/cif_core.dic
_audit_conform_dict_name         cif_core.dic
_audit_conform_dict_version      2.4.3
_audit_creation_date             2019-03-25T16:06:01-00:00
_audit_creation_method           'WinGX routine CIF_UPDATE'
_cell_angle_alpha                90
_cell_angle_beta                 94.029(2)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   11.3708(6)
_cell_length_b                   4.6026(2)
_cell_length_c                   20.5978(10)
_cell_measurement_reflns_used    9940
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      25.104
_cell_measurement_theta_min      2.974
_cell_measurement_wavelength     0.71073
_cell_volume                     1075.33(9)
_computing_cell_refinement       'SAINT v8.38A (Bruker, 2017)'
_computing_data_collection       'Apex3 v2017.3-0 (Bruker, 2017)'
_computing_data_reduction        'SAINT v8.38A (Bruker, 2017)'
_computing_molecular_graphics    'Ortep for Windows (Farrugia, 2012)'
_computing_publication_material  'WinGX publication routines (Farrugia, 2012)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXT_2018/2 (Sheldrick, 2015)'
_diffrn_ambient_temperature      150(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.996
_diffrn_measurement_device_type  'Bruker D8 Venture PHOTON II CPAD'
_diffrn_radiation_monochromator  'TRIUMPH curved--crystal'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0371
_diffrn_reflns_Laue_measured_fraction_full 0.997
_diffrn_reflns_Laue_measured_fraction_max 0.996
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       5
_diffrn_reflns_limit_k_min       -5
_diffrn_reflns_limit_l_max       24
_diffrn_reflns_limit_l_min       -24
_diffrn_reflns_number            24719
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        25.077
_diffrn_reflns_theta_max         25.077
_diffrn_reflns_theta_min         2.974
_diffrn_source                   'fine--focus tube'
_exptl_absorpt_coefficient_mu    3.786
_exptl_absorpt_correction_T_max  0.745
_exptl_absorpt_correction_T_min  0.627
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS-2016/2 (Bruker AXS )'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.557
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             508
_exptl_crystal_size_max          0.15
_exptl_crystal_size_mid          0.08
_exptl_crystal_size_min          0.04
_refine_diff_density_max         0.308
_refine_diff_density_min         -0.27
_refine_diff_density_rms         0.042
_refine_ls_abs_structure_details
;
 Refined as an inversion twin.
;
_refine_ls_abs_structure_Flack   0.013(11)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.052
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_constraints    0
_refine_ls_number_parameters     275
_refine_ls_number_reflns         3810
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.056
_refine_ls_R_factor_all          0.03
_refine_ls_R_factor_gt           0.0243
_refine_ls_shift/su_max          0
_refine_ls_shift/su_mean         0
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0209P)^2^+0.2023P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0517
_refine_ls_wR_factor_ref         0.0531
_reflns_number_gt                3475
_reflns_number_total             3810
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja9b07885_si_003.cif
_cod_data_source_block           RajanBabu2307
_cod_original_sg_symbol_H-M      'P 21'
_cod_database_code               4128962