Metal-Free Brønsted Acid-Catalyzed Rearrangement of δ-Hydroxyalkynones to 2,3-Dihydro-4 H-pyran-4-ones: Total Synthesis of Obolactone and a Catechol Pyran Isolated from Plectranthus sylvestris.
Gholap, Sachin P.; Jangid, Dashrath; Fernandes, Rodney A.; The Journal of organic chemistry 84 (2019) 3537–3551; doi:10.1021/acs.joc.8b03141

data_4033936
_publ_section_title
;
 Metal-Free Br\/onsted Acid-Catalyzed Rearrangement of \d-Hydroxyalkynones
 to 2,3-Dihydro-4 H-pyran-4-ones: Total Synthesis of Obolactone and a
 Catechol Pyran Isolated from Plectranthus sylvestris.
;
_journal_issue                   6
_journal_name_full               'The Journal of organic chemistry'
_journal_page_first              3537
_journal_page_last               3551
_journal_paper_doi               10.1021/acs.joc.8b03141
_journal_volume                  84
_journal_year                    2019
_chemical_formula_moiety         'C9 H7 Cl O3'
_chemical_formula_sum            'C9 H7 Cl O3'
_chemical_formula_weight         198.59
_space_group_crystal_system      orthorhombic
_space_group_IT_number           33
_space_group_name_Hall           'P 2c -2n'
_space_group_name_H-M_alt        'P n a 21'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     dual
_audit_creation_date             2018-10-26
_audit_creation_method
;
Olex2 1.2
(compiled 2018.05.29 svn.r3508 for OlexSys, GUI svn.r5506)
;
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            8
_cell_length_a                   6.7921(4)
_cell_length_b                   24.5033(12)
_cell_length_c                   10.1829(4)
_cell_measurement_reflns_used    7558
_cell_measurement_temperature    150
_cell_measurement_theta_max      30.0960
_cell_measurement_theta_min      2.2000
_cell_volume                     1694.73(15)
_computing_cell_refinement       'CrysAlisPro 1.171.39.46 (Rigaku OD, 2018)'
_computing_data_collection       'CrystalClear-SM Expert 2.0 r7 (Rigaku, 2011)'
_computing_data_reduction        'CrysAlisPro 1.171.39.46 (Rigaku OD, 2018)'
_computing_molecular_graphics    'Olex2 (Dolomanov et al., 2009)'
_computing_publication_material  'Olex2 (Dolomanov et al., 2009)'
_computing_structure_refinement  'ShelXL (Sheldrick, 2015)'
_computing_structure_solution    'ShelXT (Sheldrick, 2015)'
_diffrn_ambient_temperature      150.0
_diffrn_detector                 CCD
_diffrn_detector_area_resol_mean 28.5714
_diffrn_detector_type            'Rigaku Saturn724+'
_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    -98.00  39.00   0.50    8.00    --  -20.00   0.00-108.00  274
  2  \w    -20.00  10.00   0.50    8.00    --  -20.00  72.00-180.00   60
  3  \w    -53.00 -23.00   0.50    8.00    --  -20.00  72.00  36.00   60
  4  \w   -110.00  -3.00   0.50    8.00    --  -20.00   0.00  36.00  214
  5  \w     -9.00  30.00   0.50    8.00    --  -20.00  72.00 -36.00   78
  6  \w    -72.00 -42.00   0.50    8.00    --  -20.00 -72.00-180.00   60
  7  \w   -102.50  68.50   0.50    8.00    --  -20.00   0.00 108.00  342
  8  \w    -25.00   5.00   0.50    8.00    --  -20.00 -72.00 108.00   60
;
_diffrn_measurement_device       'AFC12 (Right): Kappa 3 circle'
_diffrn_measurement_device_type  'Rigaku Saturn724+ (2x2 bin mode)'
_diffrn_measurement_method       'profile data from \w-scans'
_diffrn_measurement_specimen_support 'Mitegen 50um'
_diffrn_orient_matrix_type
'CrysAlisPro convention (1999,Acta A55,543-557)'
_diffrn_orient_matrix_UB_11      0.0732582000
_diffrn_orient_matrix_UB_12      -0.0022032000
_diffrn_orient_matrix_UB_13      0.0493456000
_diffrn_orient_matrix_UB_21      -0.0017031000
_diffrn_orient_matrix_UB_22      0.0287154000
_diffrn_orient_matrix_UB_23      0.0085441000
_diffrn_orient_matrix_UB_31      -0.0744309000
_diffrn_orient_matrix_UB_32      -0.0028410000
_diffrn_orient_matrix_UB_33      0.0484206000
_diffrn_radiation_collimation    0.3
_diffrn_radiation_monochromator  Confocal
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0924
_diffrn_reflns_av_unetI/netI     0.0550
_diffrn_reflns_Laue_measured_fraction_full 0.999
_diffrn_reflns_Laue_measured_fraction_max 0.999
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       29
_diffrn_reflns_limit_k_min       -29
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            16986
_diffrn_reflns_point_group_measured_fraction_full 0.998
_diffrn_reflns_point_group_measured_fraction_max 0.998
_diffrn_reflns_theta_full        24.999
_diffrn_reflns_theta_max         24.999
_diffrn_reflns_theta_min         3.112
_diffrn_source                   'Rotating Anode'
_diffrn_source_current           24.0
_diffrn_source_power             1.2
_diffrn_source_target            Mo
_diffrn_source_type              'Rotating Anode'
_diffrn_source_voltage           50.0
_exptl_absorpt_coefficient_mu    0.417
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.82113
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018)
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    1.557
_exptl_crystal_description       plate
_exptl_crystal_F_000             816
_exptl_crystal_size_max          0.21
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.012
_refine_diff_density_max         0.352
_refine_diff_density_min         -0.320
_refine_diff_density_rms         0.097
_refine_ls_abs_structure_details
;
 Flack x determined using 980 quotients [(I+)-(I-)]/[(I+)+(I-)]
 (Parsons, Flack and Wagner, Acta Cryst. B69 (2013) 249-259).
;
_refine_ls_abs_structure_Flack   -0.02(6)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.061
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     235
_refine_ls_number_reflns         2975
_refine_ls_number_restraints     4
_refine_ls_restrained_S_all      1.066
_refine_ls_R_factor_all          0.0630
_refine_ls_R_factor_gt           0.0498
_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^)+(0.0556P)^2^+0.7350P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1118
_refine_ls_wR_factor_ref         0.1231
_reflns_Friedel_coverage         0.882
_reflns_Friedel_fraction_full    0.997
_reflns_Friedel_fraction_max     0.997
_reflns_number_gt                2607
_reflns_number_total             2975
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            jo8b03141_si_006.cif
_cod_data_source_block           raf-spg-1269_mo
_cod_depositor_comments
;

2020-04-04
Z value and formula fixed to values more according to usual
chemical conventions.                 miguel
;
_cod_original_cell_volume        1694.72(14)
_cod_original_formula_moiety     '2(C9 H7 Cl O3)'
_cod_original_formula_sum        'C18 H14 Cl2 O6'
_cod_original_formula_units_Z    4
_cod_original_formula_weight     397.19
_cod_database_code               4033936
_shelx_shelxl_version_number     2014/7
_chemical_oxdiff_formula         C10H15O2
_shelx_estimated_absorpt_t_max   0.995
_shelx_estimated_absorpt_t_min   0.918
_reflns_odcompleteness_completeness 95.01
_reflns_odcompleteness_iscentric 1
_reflns_odcompleteness_theta     31.06
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H) groups, All C(H,H) groups
2. Rigid body (RIGU) restrains
 C11, C10
 with sigma for 1-2 distances of 0.001 and sigma for 1-3 distances of 0.001
3.a Secondary CH2 refined with riding coordinates:
 C17(H17A,H17B), C8(H8A,H8B), C9(H9A,H9B), C18(H18A,H18B)
3.b Aromatic/amide H refined with riding coordinates:
 C2(H2), C3(H3), C12(H12), C1(H1), C10(H10), C11(H11)
;
_shelx_res_checksum              17261
_shelx_hkl_checksum              2944
_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
- Detector area scaling
;
_oxdiff_exptl_absorpt_empirical_full_max 1.694
_oxdiff_exptl_absorpt_empirical_full_min 0.696