Diels-Alder cycloaddition of chiral nonracemic 2,5-diketopiperazine dienes.
Morris, Erin N.; Nenninger, E. Katherine; Pike, Robert D.; Scheerer, Jonathan R.; Organic letters 13 (2011) 4430–4433; doi:10.1021/ol201768f

data_1502392
_publ_section_title
;
 Diels-Alder cycloaddition of chiral nonracemic 2,5-diketopiperazine
 dienes.
;
_journal_issue                   16
_journal_name_full               'Organic letters'
_journal_page_first              4430
_journal_page_last               4433
_journal_paper_doi               10.1021/ol201768f
_journal_volume                  13
_journal_year                    2011
_chemical_formula_moiety         'C21 H23 N3 O5'
_chemical_formula_sum            'C21 H23 N3 O5'
_chemical_formula_weight         397.42
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_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     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 106.1800(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   11.0839(2)
_cell_length_b                   7.54050(10)
_cell_length_c                   12.2852(2)
_cell_measurement_reflns_used    9183
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      68.33
_cell_measurement_theta_min      3.75
_cell_volume                     986.10(3)
_computing_cell_refinement       'SAINTPLUS (Bruker AXS, 2004)'
_computing_data_collection       'APEX2 (Bruker AXS, 2004)'
_computing_data_reduction        SAINTPLUS
_computing_molecular_graphics    'ORTEP3 (Farrugia, 1997)'
_computing_publication_material  'SHELXL97 (Sheldrick, 1997)'
_computing_structure_refinement  'XSHELL (Bruker, 2004)'
_computing_structure_solution    'SHELXS97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.985
_diffrn_measurement_device_type  'Bruker SMART APEX II CCD'
_diffrn_measurement_method       '\w and \y'
_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  0.0245
_diffrn_reflns_av_sigmaI/netI    0.0230
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            10918
_diffrn_reflns_theta_full        67.00
_diffrn_reflns_theta_max         67.00
_diffrn_reflns_theta_min         3.75
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.800
_exptl_absorpt_correction_T_max  0.9004
_exptl_absorpt_correction_T_min  0.7270
_exptl_absorpt_correction_type   numerical
_exptl_absorpt_process_details   'SADABS (Sheldrick, 2004)'
_exptl_crystal_colour            prism
_exptl_crystal_density_diffrn    1.338
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       colorless
_exptl_crystal_F_000             420
_exptl_crystal_size_max          0.43
_exptl_crystal_size_mid          0.22
_exptl_crystal_size_min          0.13
_refine_diff_density_max         0.204
_refine_diff_density_min         -0.198
_refine_diff_density_rms         0.045
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.20(12)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.053
_refine_ls_hydrogen_treatment    refall
_refine_ls_matrix_type           full
_refine_ls_number_parameters     354
_refine_ls_number_reflns         3103
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.052
_refine_ls_R_factor_all          0.0249
_refine_ls_R_factor_gt           0.0247
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0376P)^2^+0.1604P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0620
_refine_ls_wR_factor_ref         0.0621
_reflns_number_gt                3073
_reflns_number_total             3103
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol201768f_si_002.cif
_cod_data_source_block           p21
_cod_original_sg_symbol_H-M      P2(1)
_cod_database_code               1502392