Photochemical cyclization of α-amino esters to access 3-azetidinones.
Hwang, Meemie U.; Gogoi, Achyut; Scurria, Matthew; Gutierrez, Osvaldo; Scheidt, Karl A.; Chemical science 17 (2026) 6766–6772; doi:10.1039/d5sc09994c

data_1576450
_publ_section_title
;
 Photochemical cyclization of &#x3b1;-amino esters to access
 3-azetidinones.
;
_journal_issue                   13
_journal_name_full               'Chemical science'
_journal_page_first              6766
_journal_page_last               6772
_journal_paper_doi               10.1039/d5sc09994c
_journal_volume                  17
_journal_year                    2026
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C20 H27 N3 O3'
_chemical_formula_sum            'C20 H27 N3 O3'
_chemical_formula_weight         357.44
_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'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     dual
_audit_creation_date             2025-07-29
_audit_creation_method
;
Olex2 1.5
(compiled 2025.07.13 svn.rb7424aed for OlexSys, GUI svn.r7308)
;
_audit_update_record
;
2025-08-15 deposited with the CCDC.	2026-02-03 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   10.6584(6)
_cell_length_b                   10.8794(7)
_cell_length_c                   16.6188(11)
_cell_measurement_reflns_used    5468
_cell_measurement_temperature    100.00(10)
_cell_measurement_theta_max      76.8770
_cell_measurement_theta_min      4.8140
_cell_volume                     1927.1(2)
_computing_cell_refinement       'CrysAlisPro 1.171.44.114a (Rigaku OD, 2025)'
_computing_data_collection       'CrysAlisPro 1.171.44.114a (Rigaku OD, 2025)'
_computing_data_reduction        'CrysAlisPro 1.171.44.114a (Rigaku OD, 2025)'
_computing_molecular_graphics    'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.5 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2019/2 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXT  (Sheldrick, 2015)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      100.00(10)
_diffrn_detector                 'Hybrid Pixel Array Detector'
_diffrn_detector_area_resol_mean 10.0000
_diffrn_detector_type            HyPix
_diffrn_measured_fraction_theta_full 1.000
_diffrn_measured_fraction_theta_max 0.962
_diffrn_measurement_details
;
List of Runs (angles in degrees, time in seconds):

  # Type    Start    End  Width  t~exp~   \w     \q     \k     \f   Frames
  1  \w    -24.00  71.00   0.50   15.00    --   47.59 -79.00 -28.00  190
  2  \w   -109.00 -30.00   0.50   35.00    -- -103.00 119.00 170.00  158
  3  \w   -109.00 -30.00   0.50   35.00    -- -103.00 119.00 170.00  158
  4  \w     37.00 107.00   0.50   35.00    --  109.25 -79.00 -28.00  140
  5  \w     96.00 178.00   0.50   35.00    --  109.25  43.00 -54.00  164
  6  \w     37.00 110.00   0.50   35.00    --  109.25-119.00  85.00  146
  7  \w    -30.00  28.00   0.50   15.00    --  -47.59  19.00-180.00  116
  8  \w   -119.00 -73.00   0.50   15.00    --  -47.59-125.00-150.00   92
  9  \w     59.00 119.00   0.50   15.00    --   47.59 155.00 -32.00  120
 10  \w    -27.00  40.00   0.50   15.00    --   47.59 -19.00 -30.00  134
 11  \w   -174.00 -90.00   0.50   35.00    -- -103.00 -30.00-180.00  168
 12  \w    -92.00 -30.00   0.50   35.00    -- -103.00  77.00  30.00  124
 13  \w    -65.00 -30.00   0.50   35.00    -- -103.00  61.00 150.00   70
 14  \w    -65.00 -30.00   0.50   35.00    -- -103.00  61.00  30.00   70
 15  \w     97.00 178.00   0.50   35.00    --  109.25  30.00  30.00  162
 16  \w     37.00  75.00   0.50   35.00    --  109.25 -61.00 120.00   76
 17  \w     37.00 106.00   0.50   35.00    --  109.25 -94.00-120.00  138
 18  \w     37.00 111.00   0.50   35.00    --  109.25-125.00   0.00  148
 19  \w     37.00 102.00   0.50   35.00    --  109.25 -77.00-120.00  130
 20  \w   -119.00 -33.00   0.50   15.00    --  -47.59 -57.00-120.00  172
 21  \w     25.00 111.00   0.50   15.00    --   47.59  77.00 -30.00  172
 22  \w     25.00 119.00   0.50   15.00    --   47.59  77.00  60.00  188
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'XtaLAB Synergy R, DW system, HyPix'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      0.1017114000
_diffrn_orient_matrix_UB_12      0.0498958000
_diffrn_orient_matrix_UB_13      0.0573956000
_diffrn_orient_matrix_UB_21      0.0689843000
_diffrn_orient_matrix_UB_22      0.0582514000
_diffrn_orient_matrix_UB_23      -0.0717577000
_diffrn_orient_matrix_UB_31      -0.0763107000
_diffrn_orient_matrix_UB_32      0.1191136000
_diffrn_orient_matrix_UB_33      0.0112517000
_diffrn_radiation_monochromator  mirror
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.54184
_diffrn_reflns_av_R_equivalents  0.1040
_diffrn_reflns_av_unetI/netI     0.0686
_diffrn_reflns_Laue_measured_fraction_full 1.000
_diffrn_reflns_Laue_measured_fraction_max 0.962
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            16395
_diffrn_reflns_point_group_measured_fraction_full 0.996
_diffrn_reflns_point_group_measured_fraction_max 0.933
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         79.382
_diffrn_reflns_theta_min         4.858
_diffrn_source                   'Rotating-anode X-ray tube'
_diffrn_source_type              'Rigaku (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    0.674
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.26645
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.44.114a (Rigaku Oxford Diffraction, 2025)
Empirical absorption correction using spherical harmonics,
implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_colour            colourless
_exptl_crystal_colour_primary    colourless
_exptl_crystal_density_diffrn    1.232
_exptl_crystal_description       needle
_exptl_crystal_F_000             768
_exptl_crystal_recrystallization_method
'The material was recrystallised from --- by as supplied'
_exptl_crystal_size_max          0.315
_exptl_crystal_size_mid          0.025
_exptl_crystal_size_min          0.005
_refine_diff_density_max         0.390
_refine_diff_density_min         -0.288
_refine_diff_density_rms         0.071
_refine_ls_abs_structure_details
;
 Flack x determined using 951 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.7(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.063
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     232
_refine_ls_number_reflns         3911
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.063
_refine_ls_R_factor_all          0.0909
_refine_ls_R_factor_gt           0.0693
_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^)+(0.1131P)^2^+0.3578P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1790
_refine_ls_wR_factor_ref         0.1955
_reflns_Friedel_coverage         0.704
_reflns_Friedel_fraction_full    0.991
_reflns_Friedel_fraction_max     0.895
_reflns_number_gt                2934
_reflns_number_total             3911
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc09994c1.cif
_cod_data_source_block           cry0225
_cod_depositor_comments
'Adding full bibliography for 1576448--1576450.cif.'
_cod_database_code               1576450
_shelx_shelxl_version_number     2019/2
_chemical_oxdiff_formula         C20H27N3O3
_diffrn_oxdiff_digest_hkl
;
43462323637db2fafc9c70f20b6a1109903a36
;
_diffrn_oxdiff_digest_od_ed
;

;
_diffrn_oxdiff_measurement_exp_name cry0225.par
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2.a Ternary CH refined with riding coordinates:
 C1(H1), C3(H3A)
2.b Secondary CH2 refined with riding coordinates:
 C9(H9A,H9B)
2.c Aromatic/amide H refined with riding coordinates:
 C15(H15), C14(H14), C13(H13), C12(H12), C11(H11), C17(H17), C18(H18)
2.d Fitted hexagon refined as free rotating group:
 C10(C15,C14,C13,C12,C11)
2.e Idealised Me refined as rotating group:
 C6(H6A,H6B,H6C), C7(H7A,H7B,H7C), C8(H8A,H8B,H8C), C19(H19A,H19B,H19C),
 C20(H20A,H20B,H20C)
;
_shelx_res_checksum              56688
_olex2_date_sample_data_collection 2025-07-28
_olex2_date_sample_submission    2025-07-25
_olex2_diffrn_ambient_temperature_device 'Oxford Cryosystems'
_olex2_exptl_crystal_mounting_method
'The crystal was mounted on a MITIGEN holder in paratone oil'
_olex2_submission_original_sample_id cry0225
_olex2_submission_special_instructions 'No special instructions were received'
_oxdiff_exptl_absorpt_empirical_details
;
Empirical correction (ABSPACK) includes:
- Absorption correction using spherical harmonics
- Frame scaling
;
_oxdiff_exptl_absorpt_empirical_full_max 2.217
_oxdiff_exptl_absorpt_empirical_full_min 0.404