Facile synthesis of naphthoquinone spiroketals by diastereoselective oxidative [3 + 2] cycloaddition.
Wu, Kun-Liang; Wilkinson, Stephanie; Reich, Norbert O.; Pettus, Thomas R. R.; Organic letters 9 (2007) 5537–5540; doi:10.1021/ol702450d

data_1505651
_publ_section_title
;
 Facile synthesis of naphthoquinone spiroketals by diastereoselective
 oxidative [3 + 2] cycloaddition.
;
_journal_issue                   26
_journal_name_full               'Organic letters'
_journal_page_first              5537
_journal_page_last               5540
_journal_paper_doi               10.1021/ol702450d
_journal_volume                  9
_journal_year                    2007
_chemical_formula_sum            'C25 H18 O4'
_chemical_formula_weight         382.39
_chemical_name_systematic
; 
 ? 
;
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 109.225(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   17.933(4)
_cell_length_b                   5.5887(11)
_cell_length_c                   18.881(4)
_cell_measurement_temperature    293(2)
_cell_volume                     1786.8(7)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.981
_diffrn_measured_fraction_theta_max 0.981
_diffrn_measurement_device_type  'CCd area detector'
_diffrn_measurement_method       'omega scan'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.2906
_diffrn_reflns_av_sigmaI/netI    0.3228
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -19
_diffrn_reflns_limit_k_max       5
_diffrn_reflns_limit_k_min       -6
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            6938
_diffrn_reflns_theta_full        23.28
_diffrn_reflns_theta_max         23.28
_diffrn_reflns_theta_min         1.20
_exptl_absorpt_coefficient_mu    0.096
_exptl_absorpt_correction_T_max  0.525
_exptl_absorpt_correction_T_min  0.155
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   'psi scan'
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.422
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       plate
_exptl_crystal_F_000             800
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.2
_exptl_crystal_size_min          0.03
_refine_diff_density_max         0.373
_refine_diff_density_min         -0.374
_refine_diff_density_rms         0.099
_refine_ls_extinction_coef       0.011(2)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.015
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     275
_refine_ls_number_reflns         2528
_refine_ls_number_restraints     4
_refine_ls_restrained_S_all      1.015
_refine_ls_R_factor_all          0.3154
_refine_ls_R_factor_gt           0.1115
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0600P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.2074
_refine_ls_wR_factor_ref         0.2734
_reflns_number_gt                692
_reflns_number_total             2528
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol702450d-file001.cif
_cod_data_source_block           pett2
_cod_original_cell_volume        1786.8(6)
_cod_original_sg_symbol_H-M      P2(1)/c
_cod_database_code               1505651