Mechanistic investigations of bifunctional squaramide organocatalyst in asymmetric Michael reaction, observation of stereoselective retro-Michael reaction
Soos, Tibor; Csámpai, Antal; Holczbauer, Tamas; Mika, Laszlo T.; Varga, Eszter; Kardos, György; RSC Adv.  (2015) –; doi:10.1039/C5RA19593D

data_7223073
_publ_section_title
;
 Mechanistic investigations of bifunctional squaramide organocatalyst in
 asymmetric Michael reaction, observation of stereoselective retro-Michael
 reaction
;
_journal_name_full               'RSC Adv.'
_journal_paper_doi               10.1039/C5RA19593D
_journal_year                    2015
_chemical_absolute_configuration rmad
_chemical_formula_moiety         'C31 H32 N4 O3'
_chemical_formula_sum            'C31 H32 N4 O3'
_chemical_formula_weight         508.60
_chemical_melting_point          497(2)
_chemical_name_common
;
squaramide based cinchona catalyst
;
_chemical_name_systematic
3-(benzylamino)-4-(((1S)-(6-methoxyquinolin-4-yl)((2S,4S,5R)-5-vinylquinuclidin-2-yl)methyl)amino)cyclobut-3-ene-1,2-dione
_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'
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 21'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   direct
_audit_creation_method           SHELXL-2014/7
_audit_update_record
;
2015-07-13 deposited with the CCDC.
2015-10-27 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   8.7790(2)
_cell_length_b                   11.6400(2)
_cell_length_c                   26.194(1)
_cell_measurement_reflns_used    21339
_cell_measurement_temperature    295(2)
_cell_measurement_theta_max      71.50
_cell_measurement_theta_min      6.50
_cell_volume                     2676.70(13)
_computing_cell_refinement       'Crystal Clear V.1.4.1 (Rigaku/MSC, 2007)'
_computing_data_collection       'Crystal Clear V.1.4.1 (Rigaku/MSC, 2007)'
_computing_data_reduction        'Crystal Clear V.1.4.1 (Rigaku/MSC, 2007)'
_computing_molecular_graphics    'PLATON (Spek, 2009)'
_computing_publication_material  'PLATON (Spek, 2009)'
_computing_structure_refinement  'SHELXL-2014/7 (Sheldrick, 2014)'
_computing_structure_solution    'SHELXS-2014/7 (Sheldrick, 2014)'
_diffrn_ambient_temperature      295(2)
_diffrn_detector_area_resol_mean 10.0000
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  RAXIS-RAPID
_diffrn_measurement_method       dtprofit.ref
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           CuK\a
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0293
_diffrn_reflns_av_unetI/netI     0.0304
_diffrn_reflns_Laue_measured_fraction_full 0.995
_diffrn_reflns_Laue_measured_fraction_max 0.995
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            23228
_diffrn_reflns_point_group_measured_fraction_full 0.993
_diffrn_reflns_point_group_measured_fraction_max 0.993
_diffrn_reflns_theta_full        56.906
_diffrn_reflns_theta_max         56.906
_diffrn_reflns_theta_min         6.538
_diffrn_source                   'NORMAL-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.659
_exptl_absorpt_correction_T_max  0.941
_exptl_absorpt_correction_T_min  0.826
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   'Rigaku, (2007)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.262
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       platelet
_exptl_crystal_F_000             1080
_exptl_crystal_recrystallization_method
'Re-crystallisation from solvent: methanol/acetone'
_exptl_crystal_size_max          0.250
_exptl_crystal_size_mid          0.250
_exptl_crystal_size_min          0.050
_refine_diff_density_max         0.183
_refine_diff_density_min         -0.189
_refine_diff_density_rms         0.043
_refine_ls_abs_structure_details
;
 Flack x determined using 1031 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.01(5)
_refine_ls_extinction_coef       0.0033(3)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     'SHELXL-2014/7 (Sheldrick 2014'
_refine_ls_goodness_of_fit_ref   1.192
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     345
_refine_ls_number_reflns         3579
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.192
_refine_ls_R_factor_all          0.0547
_refine_ls_R_factor_gt           0.0333
_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^)+(0.0240P)^2^+0.9144P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0657
_refine_ls_wR_factor_ref         0.0900
_reflns_Friedel_coverage         0.723
_reflns_Friedel_fraction_full    0.990
_reflns_Friedel_fraction_max     0.990
_reflns_number_gt                2886
_reflns_number_total             3579
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            c5ra19593d2.cif
_cod_data_source_block           shelx
_cod_original_cell_volume        2676.7(1)
_cod_database_code               7223073
_shelx_shelxl_version_number     2014/7
_shelx_estimated_absorpt_t_min   0.853
_shelx_estimated_absorpt_t_max   0.968
_exptl_absorpt_special_details
;
'Num abs corr by T. Higashi (Rigaku, 2007)'
;
_shelx_res_checksum              19438