Enantioselective lactonization catalyzed by chiral N-heterocyclic carbenes enables access to inherently chiral eight-membered lactones.
Dočekal, Vojtěch; Kurčina, Adam; Císařová, Ivana; Veselý, Jan; Chemical science 16 (2025) 17369–17373; doi:10.1039/d5sc05037e

data_1575946
_publ_section_title
;
 Enantioselective lactonization catalyzed by chiral N-heterocyclic
 carbenes enables access to inherently chiral eight-membered lactones.
;
_journal_issue                   37
_journal_name_full               'Chemical science'
_journal_page_first              17369
_journal_page_last               17373
_journal_paper_doi               10.1039/d5sc05037e
_journal_volume                  16
_journal_year                    2025
_chemical_absolute_configuration ad
_chemical_compound_source        'synthesized by the authors'
_chemical_formula_moiety         'C19 H12 O2'
_chemical_formula_sum            'C19 H12 O2'
_chemical_formula_weight         272.29
_space_group_crystal_system      monoclinic
_space_group_IT_number           5
_space_group_name_Hall           'C 2y'
_space_group_name_H-M_alt        'C 1 2 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     'Intrinsic Phasing'
_audit_creation_method
;FinalCif 2024.9-1 by Daniel Kratzert, Freiburg 2025, 
https://dkratzert.de/finalcif.html
;
_audit_update_record
;
2025-06-23 deposited with the CCDC.	2025-08-25 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 97.8140(10)
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   16.6502(7)
_cell_length_b                   7.3452(3)
_cell_length_c                   21.9150(9)
_cell_measurement_reflns_used    9912
_cell_measurement_temperature    100.14999999999998
_cell_measurement_theta_max      79.3049
_cell_measurement_theta_min      5.3632
_cell_measurement_wavelength     1.54178
_cell_volume                     2655.30(19)
_computing_cell_refinement       'SAINT V8.41 (Bruker AXS LLC)'
_computing_data_collection       'Bruker Instrument Service v8.5.5.6'
_computing_data_reduction        'SAINT V8.41 (Bruker AXS LLC)'
_computing_molecular_graphics    'shelXle (C.B. Huebschle, rev 1503)'
_computing_structure_refinement  'SHELXL-2019/2 (Sheldrick, 2019)'
_computing_structure_solution    'SHELXT 2018/2 (Sheldrick, 2018)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      100(2)
_diffrn_detector                 CPAD
_diffrn_detector_area_resol_mean 7.391
_diffrn_detector_type            'Bruker PHOTON III'
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.989
_diffrn_measurement_details
;<Phi   scan: start= 360.0; len= 180.0; end= 540.0 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  25.000 deg omega= 360.000 deg chi=  54.740 deg] 
measure for 1.0 seconds; frame angle 1.00 degrees, wavelength=1.54184>
<Phi   scan: start= 360.0; len= 180.0; end= 540.0 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  27.500 deg omega= 360.000 deg chi=  54.740 deg] 
measure for 1.0 seconds; frame angle 1.00 degrees, wavelength=1.54184>
<Phi   scan: start= 180.0; len= 180.0; end= 360.0 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  27.500 deg omega= 360.000 deg chi=  54.740 deg] 
measure for 1.0 seconds; frame angle 1.00 degrees, wavelength=1.54184>
<Omega scan: start=   1.4; len= 112.0; end= 113.4 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 360.000 deg chi=  65.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Phi   scan: start= 308.0; len= 216.0; end= 524.0 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg omega= 107.777 deg chi= -24.000 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   1.4; len= 112.0; end= 113.4 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 160.000 deg chi=  65.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   1.4; len= 112.0; end= 113.4 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 320.000 deg chi=  65.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Phi   scan: start= 360.0; len=   0.5; end= 360.5 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta= -23.787 deg omega=  58.298 deg chi= -44.500 deg] 
measure for 4.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=  90.6; len=  83.5; end= 174.1 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  46.287 deg phi= 180.000 deg chi= -44.500 deg] 
measure for 11.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Phi   scan: start=  44.0; len= 184.0; end= 228.0 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg omega=  11.496 deg chi=  24.000 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=  90.6; len=  83.5; end= 174.1 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  46.287 deg phi=  90.000 deg chi= -44.500 deg] 
measure for 11.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start= 340.9; len= 107.0; end= 447.9 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  41.282 deg phi= 340.706 deg chi=  56.004 deg] 
measure for 9.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   4.6; len=  74.5; end=  79.1 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 252.000 deg chi=  68.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   1.4; len= 112.0; end= 113.4 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi=  40.000 deg chi=  65.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   1.4; len= 112.0; end= 113.4 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 280.000 deg chi=  65.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   4.6; len=  74.5; end=  79.1 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 108.000 deg chi=  68.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   1.4; len= 112.0; end= 113.4 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi=  80.000 deg chi=  65.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Phi   scan: start= 284.0; len= 264.0; end= 548.0 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg omega= 105.633 deg chi= -44.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   4.6; len=  74.5; end=  79.1 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 324.000 deg chi=  68.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=  75.6; len=  98.5; end= 174.1 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  38.787 deg phi= 270.000 deg chi= -44.500 deg] 
measure for 8.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   1.4; len= 112.0; end= 113.4 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 240.000 deg chi=  65.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   4.6; len=  74.5; end=  79.1 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 180.000 deg chi=  68.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start=   1.4; len= 112.0; end= 113.4 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.787 deg phi= 120.000 deg chi=  65.500 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
<Omega scan: start= 356.7; len=  92.5; end= 449.2 at [Counterclockwise Eulerian 
angles: dx= 40.00 mm theta=  53.688 deg phi=  83.080 deg chi=  53.294 deg] 
measure for 15.0 seconds; frame angle 0.50 degrees, wavelength=1.54184>
;
_diffrn_measurement_device       'KAPPA diffractometer'
_diffrn_measurement_device_type  'Bruker D8 VENTURE'
_diffrn_measurement_method       '\w and \f scans'
_diffrn_radiation_monochromator  'multilayer mirror'
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           'Cu K\a'
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0183
_diffrn_reflns_av_unetI/netI     0.0198
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.989
_diffrn_reflns_limit_h_max       21
_diffrn_reflns_limit_h_min       -20
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       27
_diffrn_reflns_limit_l_min       -27
_diffrn_reflns_number            27614
_diffrn_reflns_point_group_measured_fraction_full 0.981
_diffrn_reflns_point_group_measured_fraction_max 0.952
_diffrn_reflns_reduction_process narrow-frame
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         79.54
_diffrn_reflns_theta_min         2.035
_diffrn_source                   'microfocus sealed tube'
_diffrn_source_current           1.1
_diffrn_source_target            Cu
_diffrn_source_type              'INCOATEC I\mS Diamond II'
_diffrn_source_voltage           50
_exptl_absorpt_coefficient_mu    0.7
_exptl_absorpt_correction_T_max  0.913
_exptl_absorpt_correction_T_min  0.718
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;Krause, L., Herbst-Irmer, R., Sheldrick, G. M., Stalke, D. (2015).
"Comparison of silver and molybdenum microfocus X-ray sources for single-crystal
 structure determination"
J. Appl. Cryst. 48, 3-10.
doi:10.1107/S1600576714022985
;
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.362
_exptl_crystal_description       prism
_exptl_crystal_F_000             1136
_exptl_crystal_size_max          0.506
_exptl_crystal_size_mid          0.275
_exptl_crystal_size_min          0.132
_refine_diff_density_max         0.191
_refine_diff_density_min         -0.186
_refine_diff_density_rms         0.039
_refine_ls_abs_structure_details
;
 Flack x determined using 2418 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   0.03(5)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.039
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     379
_refine_ls_number_reflns         5527
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.039
_refine_ls_R_factor_all          0.0300
_refine_ls_R_factor_gt           0.0300
_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^)+(0.0450P)^2^+1.2961P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0796
_refine_ls_wR_factor_ref         0.0796
_reflns_Friedel_coverage         0.784
_reflns_Friedel_fraction_full    0.961
_reflns_Friedel_fraction_max     0.909
_reflns_number_gt                5524
_reflns_number_total             5527
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d5sc05037e3.cif
_cod_data_source_block           cu_vd3247cu2_vesely_a
_cod_original_sg_symbol_H-M      'C 2'
_cod_database_code               1575946
_shelx_shelxl_version_number     2019/3
_exptl_bruker_absorpt_correction_t_ratio 0.8406
_shelx_estimated_absorpt_t_min   0.718
_shelx_estimated_absorpt_t_max   0.913
_bruker_diffrn_measurement_temperature_device 'Oxford Cryostream 1000'
_diffrn_measurement_bruker_total_exposure_time 69111.0
_diffrn_reflns_bruker_av_norm_i  368079.168
_diffrn_reflns_bruker_number_gt  31530
_computing_bruker_data_scaling
'SADABS-2016/2 - Bruker AXS area detector scaling and absorption correction'
_geom_details
; All esds (except the esd in the dihedral angle between two l.s. planes)
 are estimated using the full covariance matrix.  The cell esds are taken
 into account individually in the estimation of esds in distances, angles
 and torsion angles; correlations between esds in cell parameters are only
 used when they are defined by crystal symmetry.  An approximate (isotropic)
 treatment of cell esds is used for estimating esds involving l.s. planes.
;
_shelx_res_checksum              78287