Ir-Catalyzed Double Asymmetric Hydrogenation of 3,6-Dialkylidene-2,5-diketopiperazines for Enantioselective Synthesis of Cyclic Dipeptides.
Ge, Yao; Han, Zhaobin; Wang, Zheng; Ding, Kuiling; Journal of the American Chemical Society 141 (2019) 8981–8988; doi:10.1021/jacs.9b02920

data_4127593
_publ_section_title
;
 Ir-Catalyzed Double Asymmetric Hydrogenation of
 3,6-Dialkylidene-2,5-diketopiperazines for Enantioselective Synthesis of
 Cyclic Dipeptides.
;
_journal_issue                   22
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              8981
_journal_page_last               8988
_journal_paper_doi               10.1021/jacs.9b02920
_journal_volume                  141
_journal_year                    2019
_chemical_formula_sum            'C20 H20 N2 O2'
_chemical_formula_weight         320.38
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2ybc'
_space_group_name_H-M_alt        'P 1 21/c 1'
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2013
_cell_angle_alpha                90
_cell_angle_beta                 100.429(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   15.2310(7)
_cell_length_b                   14.0585(6)
_cell_length_c                   7.9797(4)
_cell_measurement_reflns_used    7697
_cell_measurement_temperature    296(2)
_cell_measurement_theta_max      54.863
_cell_measurement_theta_min      5.945
_cell_volume                     1680.43(14)
_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-2013 (Sheldrick, 2013)'
_computing_structure_solution    'SHELXS-97 (Sheldrick 2008)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.987
_diffrn_measured_fraction_theta_max 0.988
_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  0.0359
_diffrn_reflns_av_unetI/netI     0.0252
_diffrn_reflns_Laue_measured_fraction_full 0.987
_diffrn_reflns_Laue_measured_fraction_max 0.988
_diffrn_reflns_limit_h_max       16
_diffrn_reflns_limit_h_min       -18
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       9
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            17379
_diffrn_reflns_point_group_measured_fraction_full 0.987
_diffrn_reflns_point_group_measured_fraction_max 0.988
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         26.000
_diffrn_reflns_theta_min         3.082
_exptl_absorpt_coefficient_mu    0.083
_exptl_absorpt_correction_T_max  0.7456
_exptl_absorpt_correction_T_min  0.6499
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   sadabs
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.266
_exptl_crystal_description       prismatic
_exptl_crystal_F_000             680
_exptl_crystal_size_max          0.200
_exptl_crystal_size_mid          0.170
_exptl_crystal_size_min          0.130
_refine_diff_density_max         0.138
_refine_diff_density_min         -0.120
_refine_diff_density_rms         0.025
_refine_ls_extinction_coef       0.038(6)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.034
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     220
_refine_ls_number_reflns         3262
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.034
_refine_ls_R_factor_all          0.0491
_refine_ls_R_factor_gt           0.0397
_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^)+(0.0369P)^2^+0.3807P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0930
_refine_ls_wR_factor_ref         0.1000
_reflns_Friedel_coverage         0.000
_reflns_number_gt                2737
_reflns_number_total             3262
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja9b02920_si_004.cif
_cod_data_source_block           d8v18766
_cod_database_code               4127593
_shelx_estimated_absorpt_t_min   0.984
_shelx_estimated_absorpt_t_max   0.989
_shelxl_version_number           2013-4
_shelx_res_checksum              97202
_shelx_hkl_checksum              27260