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_7159254
_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 H26 Cl4 N2 O6, C H Cl3, 0.5(C5 H12)'
_chemical_formula_sum            'C37.5 H33 Cl7 N2 O6'
_chemical_formula_weight         855.81
_space_group_crystal_system      monoclinic
_space_group_IT_number           15
_space_group_name_Hall           '-I 2ya'
_space_group_name_H-M_alt        'I 1 2/a 1'
_atom_sites_solution_hydrogens   geom
_audit_creation_method           SHELXL-2018/1
_audit_update_record
;
2022-05-31 deposited with the CCDC.	2023-03-22 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 91.256(3)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   18.0917(6)
_cell_length_b                   12.0597(5)
_cell_length_c                   35.4251(10)
_cell_measurement_reflns_used    4873
_cell_measurement_temperature    123(1)
_cell_measurement_theta_max      27.0110
_cell_measurement_theta_min      2.8880
_cell_volume                     7727.2(5)
_computing_cell_refinement       'CrysAlisPro 1.171.39.44a (Rigaku OD, 2018)'
_computing_data_collection       'CrysAlisPro 1.171.39.44a (Rigaku OD, 2018)'
_computing_data_reduction        'CrysAlisPro 1.171.39.44a (Rigaku OD, 2018)'
_computing_publication_material  'SHELXL-2018/1 (Sheldrick, 2018)'
_computing_structure_refinement  'SHELXL-2018/1 (Sheldrick, 2018)'
_computing_structure_solution    'SHELXT-2014/5 (Sheldrick, 2015)'
_diffrn_ambient_temperature      123(1)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 16.0655
_diffrn_detector_type            Sapphire3
_diffrn_measured_fraction_theta_full 0.992
_diffrn_measured_fraction_theta_max 0.969
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'Xcalibur, Sapphire3'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0552
_diffrn_reflns_av_unetI/netI     0.0727
_diffrn_reflns_Laue_measured_fraction_full 0.992
_diffrn_reflns_Laue_measured_fraction_max 0.969
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -22
_diffrn_reflns_limit_k_max       14
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -43
_diffrn_reflns_number            19828
_diffrn_reflns_point_group_measured_fraction_full 0.992
_diffrn_reflns_point_group_measured_fraction_max 0.969
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         25.999
_diffrn_reflns_theta_min         2.864
_diffrn_source                   'fine-focus sealed X-ray tube'
_diffrn_source_type              'Enhance (Mo) X-ray Source'
_exptl_absorpt_coefficient_mu    0.562
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.89319
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.39.44a (Rigaku Oxford Diffraction, 2018)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.471
_exptl_crystal_description       plate
_exptl_crystal_F_000             3512
_exptl_crystal_size_max          0.160
_exptl_crystal_size_mid          0.085
_exptl_crystal_size_min          0.022
_refine_diff_density_max         0.511
_refine_diff_density_min         -0.483
_refine_diff_density_rms         0.068
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.017
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     528
_refine_ls_number_reflns         7362
_refine_ls_number_restraints     262
_refine_ls_restrained_S_all      1.003
_refine_ls_R_factor_all          0.0841
_refine_ls_R_factor_gt           0.0485
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0433P)^2^+4.5909P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0971
_refine_ls_wR_factor_ref         0.1121
_reflns_Friedel_coverage         0.000
_reflns_number_gt                5093
_reflns_number_total             7362
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d3ob00284e2.cif
_cod_data_source_block           p1158
_cod_depositor_comments
'Adding full bibliography for 7159254--7159256.cif.'
_cod_original_sg_symbol_H-M      'I 2/a'
_cod_original_formula_sum        'C37.50 H33 Cl7 N2 O6'
_cod_database_code               7159254
_shelx_shelxl_version_number     2018/1
_shelx_estimated_absorpt_t_min   0.915
_shelx_estimated_absorpt_t_max   0.988
_shelx_res_checksum              32793
_shelx_hkl_checksum              88422