Stereoselective synthesis of the spirocyclic core of 13-desmethyl spirolide C using an aza-Claisen rearrangement and an <i>exo</i>-selective Diels-Alder cycloaddition.
Earl, Andrew D. W.; Li, Freda F.; Ma, Chao; Furkert, Daniel P.; Brimble, Margaret A.; Organic & biomolecular chemistry 21 (2023) 1222–1234; doi:10.1039/d2ob01992b

data_7159070
_publ_section_title
;
 Stereoselective synthesis of the spirocyclic core of 13-desmethyl
 spirolide C using an aza-Claisen rearrangement and an
 <i>exo</i>-selective Diels-Alder cycloaddition.
;
_journal_issue                   6
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              1222
_journal_page_last               1234
_journal_paper_doi               10.1039/d2ob01992b
_journal_volume                  21
_journal_year                    2023
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C32 H53 N O5 Si2'
_chemical_formula_sum            'C32 H53 N O5 Si2'
_chemical_formula_weight         587.93
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2yb'
_space_group_name_H-M_alt        'P 1 21 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_audit_creation_date             2022-09-01
_audit_creation_method
;
Olex2 1.3
(compiled 2020.11.12 svn.r5f609507 for OlexSys, GUI svn.r6408)
;
_audit_update_record
;
2022-09-07 deposited with the CCDC.	2023-01-04 downloaded from the CCDC.
;
_cell_angle_alpha                90
_cell_angle_beta                 101.794(2)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   8.01200(10)
_cell_length_b                   11.4236(2)
_cell_length_c                   18.6445(3)
_cell_measurement_reflns_used    11727
_cell_measurement_temperature    104.3(8)
_cell_measurement_theta_max      74.0120
_cell_measurement_theta_min      4.5570
_cell_volume                     1670.43(5)
_computing_cell_refinement       'CrysAlisPro 1.171.40.53 (Rigaku OD, 2019)'
_computing_data_collection       'CrysAlisPro 1.171.40.53 (Rigaku OD, 2019)'
_computing_data_reduction        'CrysAlisPro 1.171.40.53 (Rigaku OD, 2019)'
_computing_molecular_graphics    'Olex2 1.3 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 1.3 (Dolomanov et al., 2009)'
_computing_structure_refinement  'SHELXL 2018/3 (Sheldrick, 2015)'
_computing_structure_solution    'SHELXS  (Sheldrick, 2008)'
_diffrn_ambient_environment      N~2~
_diffrn_ambient_temperature      104.3(8)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 5.8140
_diffrn_detector_type            'Pilatus 200K'
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_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     -4.00  31.00   0.50    0.60    --   47.48 -68.00 104.00   70
  2  \w     33.00  59.00   0.50    2.00    --  101.53 -68.00 104.00   52
  3  \w    100.00 125.00   0.50    2.00    --  101.53 -68.00 104.00   50
  4  \w     88.00 123.00   0.50    2.00    --  101.53 -77.00   0.00   70
  5  \w     78.00 127.00   0.50    2.00    --  101.53 -77.00 -60.00   98
  6  \w     82.00 152.00   0.50    2.00    --  101.53  30.00-150.00  140
  7  \w    122.00 170.00   0.50    2.00    --  101.53  61.00 -90.00   96
  8  \w    138.00 164.00   0.50    2.00    --  101.53  77.00 -30.00   52
  9  \w    143.00 169.00   0.50    2.00    --  101.53  77.00  30.00   52
 10  \w    107.00 133.00   0.50    2.00    --  101.53  61.00  30.00   52
 11  \w     76.00 140.00   0.50    2.00    --  101.53  77.00  30.00  128
 12  \w     84.00 110.00   0.50    2.00    --  101.53  61.00 -90.00   52
 13  \w     79.00 124.00   0.50    2.00    --  101.53  77.00 -30.00   90
 14  \w    104.00 176.00   0.50    2.00    --  101.53 111.00 -90.00  144
 15  \w     83.00 176.00   0.50    2.00    --  101.53  30.00-180.00  186
 16  \w     78.00 131.00   0.50    2.00    --  101.53  68.00-122.00  106
 17  \w     58.00 106.00   0.50    0.60    --   47.48  68.00-122.00   96
 18  \w     26.00  73.00   0.50    2.00    --  101.53 -77.00   0.00   94
 19  \w     26.00  51.00   0.50    2.00    --  101.53 -77.00 -60.00   50
 20  \w     26.00  92.00   0.50    2.00    --  101.53 -95.00-150.00  132
 21  \w     23.00  81.00   0.50    2.00    --  101.53 -95.00-180.00  116
 22  \w    -70.00  23.00   0.50    0.60    --  -47.48  68.00-122.00  186
 23  \w    -72.00 -34.00   0.50    2.00    --  -90.25  68.00-122.00   76
 24  \w    -85.00 -11.00   0.50    2.00    --  -90.25 111.00   0.00  148
 25  \w    -87.00 -11.00   0.50    2.00    --  -90.25 111.00  30.00  152
 26  \w   -106.00 -42.00   0.50    2.00    --  -90.25  77.00 -30.00  128
 27  \w   -128.00 -25.00   0.50    0.60    --  -47.48 -19.00 -60.00  206
 28  \w    -80.00 -42.00   0.50    0.60    --  -47.48 -57.00  60.00   76
 29  \w    -72.00 -47.00   0.50    0.60    --  -47.48 -68.00 104.00   50
 30  \w   -102.00 -75.00   0.50    0.60    --  -47.48-125.00  60.00   54
 31  \w   -122.00 -70.00   0.50    2.00    --  -90.25 -45.00 -30.00  104
 32  \w   -135.00 -69.00   0.50    2.00    --  -90.25 -45.00 -60.00  132
 33  \w   -121.00 -71.00   0.50    0.60    --  -47.48-125.00-180.00  100
 34  \w   -158.00-133.00   0.50    2.00    --  -90.25 -45.00 -30.00   50
 35  \w   -161.00 -88.00   0.50    2.00    --  -90.25 -30.00   0.00  146
 36  \w   -134.00 -80.00   0.50    2.00    --  -90.25 -68.00 104.00  108
 37  \w   -145.00-110.00   0.50    2.00    --  -90.25 -95.00  60.00   70
 38  \w   -158.00-103.00   0.50    2.00    --  -90.25 -45.00 120.00  110
;
_diffrn_measurement_device       'four-circle diffractometer'
_diffrn_measurement_device_type  'XtaLAB Synergy, Dualflex, Pilatus 200K'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      -0.1163535000
_diffrn_orient_matrix_UB_12      -0.1026721000
_diffrn_orient_matrix_UB_13      0.0115775000
_diffrn_orient_matrix_UB_21      -0.1037780000
_diffrn_orient_matrix_UB_22      0.0161452000
_diffrn_orient_matrix_UB_23      -0.0785711000
_diffrn_orient_matrix_UB_31      0.1195368000
_diffrn_orient_matrix_UB_32      -0.0859440000
_diffrn_orient_matrix_UB_33      -0.0285546000
_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  0.0477
_diffrn_reflns_av_unetI/netI     0.0435
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       22
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            21914
_diffrn_reflns_point_group_measured_fraction_full 0.999
_diffrn_reflns_point_group_measured_fraction_max 0.999
_diffrn_reflns_theta_full        67.684
_diffrn_reflns_theta_max         68.250
_diffrn_reflns_theta_min         5.641
_diffrn_source                   'micro-focus sealed X-ray tube'
_diffrn_source_type              'PhotonJet (Cu) X-ray Source'
_exptl_absorpt_coefficient_mu    1.262
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.98420
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.40.53 (Rigaku Oxford Diffraction, 2019)
Empirical absorption correction using spherical harmonics,
 implemented in SCALE3 ABSPACK scaling algorithm.
;
_exptl_crystal_density_diffrn    1.169
_exptl_crystal_description       block
_exptl_crystal_F_000             640
_exptl_crystal_recrystallization_method 'Re-crystallisation from solvent'
_exptl_crystal_size_max          0.08
_exptl_crystal_size_mid          0.08
_exptl_crystal_size_min          0.08
_refine_diff_density_max         0.215
_refine_diff_density_min         -0.188
_refine_diff_density_rms         0.035
_refine_ls_abs_structure_details
;
 Refined as an inversion twin.
;
_refine_ls_abs_structure_Flack   0.10(3)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.037
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     372
_refine_ls_number_reflns         6128
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.037
_refine_ls_R_factor_all          0.0340
_refine_ls_R_factor_gt           0.0311
_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^)+(0.0334P)^2^+0.2629P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0735
_refine_ls_wR_factor_ref         0.0747
_reflns_Friedel_coverage         0.897
_reflns_Friedel_fraction_full    1.000
_reflns_Friedel_fraction_max     0.999
_reflns_number_gt                5759
_reflns_number_total             6128
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            d2ob01992b2.cif
_cod_data_source_block           ade558
_cod_depositor_comments          'Adding full bibliography for 7159070.cif.'
_cod_database_code               7159070
_shelx_shelxl_version_number     2018/3
_chemical_oxdiff_formula         C32H53NO5Si2
_shelx_estimated_absorpt_t_max   0.906
_shelx_estimated_absorpt_t_min   0.906
_reflns_odcompleteness_completeness 99.94
_reflns_odcompleteness_iscentric 1
_reflns_odcompleteness_theta     68.13
_olex2_refinement_description
;
1. Twinned data refinement
 Scales: 0.90(3)
 0.10(3)
2. 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
3.a Ternary CH refined with riding coordinates:
 C12(H12)
3.b Secondary CH2 refined with riding coordinates:
 C8(H8A,H8B), C9(H9A,H9B), C13(H13A,H13B), C21(H21A,H21B), C22(H22A,H22B),
 C23(H23A,H23B), C24(H24A,H24B), C27(H27A,H27B)
3.c Aromatic/amide H refined with riding coordinates:
 C11(H11), C29(H29), C30(H30), C31(H31), C32(H32), C33(H33)
3.d Idealised Me refined as rotating group:
 C2(H2A,H2B,H2C), C3(H3A,H3B,H3C), C4(H4A,H4B,H4C), C6(H6A,H6B,H6C), C7(H7A,
 H7B,H7C), C14(H14A,H14B,H14C), C15(H15A,H15B,H15C), C17(H17A,H17B,H17C),
 C18(H18A,H18B,H18C), C19(H19A,H19B,H19C)
;
_shelx_res_checksum              97433
_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 1.145
_oxdiff_exptl_absorpt_empirical_full_min 0.907