Synthesis of 1,2-diaminotruxinic δ-cyclobutanes by BF<sub>3</sub>-controlled [2 + 2]-photocycloaddition of 5(4<i>H</i>)-oxazolones and stereoselective expansion of δ-cyclobutanes to give highly substituted pyrrolidine-2,5-dicarboxylates.
Sierra, Sonia; López, Rosa; Gómez-Bengoa, Enrique; Falvello, Larry R.; Urriolabeitia, Esteban P.; Organic & biomolecular chemistry 21 (2023) 3203–3213; doi:10.1039/d3ob00284e

data_7159255
_publ_section_title
;
 Synthesis of 1,2-diaminotruxinic &#x3b4;-cyclobutanes by
 BF<sub>3</sub>-controlled [2 + 2]-photocycloaddition of
 5(4<i>H</i>)-oxazolones and stereoselective expansion of
 &#x3b4;-cyclobutanes to give highly substituted
 pyrrolidine-2,5-dicarboxylates.
;
_journal_issue                   15
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              3203
_journal_page_last               3213
_journal_paper_doi               10.1039/d3ob00284e
_journal_volume                  21
_journal_year                    2023
_chemical_formula_moiety         'C34 H28 F2 N2 O6,C H2 Cl2'
_chemical_formula_sum            'C35 H30 Cl2 F2 N2 O6'
_chemical_formula_weight         683.51
_space_group_crystal_system      triclinic
_space_group_IT_number           2
_space_group_name_Hall           '-P 1'
_space_group_name_H-M_alt        'P -1'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2019/2
_audit_update_record
;
2022-06-06 deposited with the CCDC.	2023-03-22 downloaded from the CCDC.
;
_cell_angle_alpha                96.5540(10)
_cell_angle_beta                 96.0450(10)
_cell_angle_gamma                105.3120(10)
_cell_formula_units_Z            2
_cell_length_a                   9.6404(8)
_cell_length_b                   10.1481(9)
_cell_length_c                   17.4357(15)
_cell_measurement_reflns_used    5247
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      28.815
_cell_measurement_theta_min      2.212
_cell_volume                     1618.0(2)
_computing_cell_refinement       'SAINT+ in APEX3 v. 2017.3 (Bruker AXS, 2008)'
_computing_data_collection       'SMART in APEX2 v. 2008.4 (Bruker AXS, 2008)'
_computing_data_reduction        'SAINT+ in APEX3 v. 2017.3 (Bruker AXS, 2008)'
_computing_molecular_graphics    'ORTEP-3 (farrugia, 2012)'
_computing_publication_material  'XCIF program, PLATON(Spek, 1998)'
_computing_structure_refinement  'SHELXL-2019/2 (Sheldrick, 2019)'
_computing_structure_solution    'SHELXS-2013 (Sheldrick, 2013)'
_diffrn_ambient_temperature      100(2)
_diffrn_detector_area_resol_mean 8.26
_diffrn_measured_fraction_theta_full 0.973
_diffrn_measured_fraction_theta_max 0.871
_diffrn_measurement_device_type  'Bruker APEX CCD system'
_diffrn_measurement_method       'narrow \w frames'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0801
_diffrn_reflns_av_unetI/netI     0.1178
_diffrn_reflns_Laue_measured_fraction_full 0.973
_diffrn_reflns_Laue_measured_fraction_max 0.871
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       23
_diffrn_reflns_limit_l_min       -23
_diffrn_reflns_number            17405
_diffrn_reflns_point_group_measured_fraction_full 0.973
_diffrn_reflns_point_group_measured_fraction_max 0.871
_diffrn_reflns_theta_full        27.500
_diffrn_reflns_theta_max         29.381
_diffrn_reflns_theta_min         2.104
_exptl_absorpt_coefficient_mu    0.261
_exptl_absorpt_correction_T_max  0.9583
_exptl_absorpt_correction_T_min  0.5939
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
 SADABS 2016/2: Krause, L., Herbst-Irmer, R., Sheldrick G.M. & Stalke D.,
 J. Appl. Cryst. 48 (2015) 3-10
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.403
_exptl_crystal_description       plate
_exptl_crystal_F_000             708
_exptl_crystal_size_max          0.26
_exptl_crystal_size_mid          0.23
_exptl_crystal_size_min          0.19
_refine_diff_density_max         0.580
_refine_diff_density_min         -0.554
_refine_diff_density_rms         0.095
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.023
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     407
_refine_ls_number_reflns         7779
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.023
_refine_ls_R_factor_all          0.1289
_refine_ls_R_factor_gt           0.0851
_refine_ls_shift/su_max          0.004
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.1467P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2397
_refine_ls_wR_factor_ref         0.2648
_reflns_Friedel_coverage         0.000
_reflns_number_gt                4414
_reflns_number_total             7779
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d3ob00284e2.cif
_cod_data_source_block           cmpnd_2o
_cod_depositor_comments
'Adding full bibliography for 7159254--7159256.cif.'
_cod_database_code               7159255
_shelx_shelxl_version_number     2019/2
_shelx_res_checksum              55667
_shelx_hkl_checksum              26432
_shelx_fab_checksum              24404