Organocatalytic 1,4-conjugate addition of ascorbic acid to α,β-unsaturated aldehydes: bio-inspired total syntheses of leucodrin, leudrin and proposed structure of dilaspirolactone.
Wang, Zhaofeng; Zhao, Kun; Fu, Junkai; Zhang, Junlin; Yin, Weiyu; Tang, Yefeng; Organic & biomolecular chemistry 11 (2013) 2093–2097; doi:10.1039/c3ob00046j

data_7152838
_publ_section_title
;
 Organocatalytic 1,4-conjugate addition of ascorbic acid to
 \a,\b-unsaturated aldehydes: bio-inspired total syntheses of leucodrin,
 leudrin and proposed structure of dilaspirolactone.
;
_journal_issue                   13
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              2093
_journal_page_last               2097
_journal_paper_doi               10.1039/c3ob00046j
_journal_volume                  11
_journal_year                    2013
_chemical_absolute_configuration rm
_chemical_formula_moiety         'C22 H22 O8'
_chemical_formula_sum            'C22 H22 O8'
_chemical_formula_weight         414.40
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 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                 95.955(5)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   6.690(2)
_cell_length_b                   7.080(2)
_cell_length_c                   20.692(6)
_cell_measurement_reflns_used    3470
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      27.48
_cell_measurement_theta_min      1.98
_cell_volume                     974.8(5)
_computing_cell_refinement       'CrystalClear (Rigaku Inc., 2007)'
_computing_data_collection       'CrystalClear (Rigaku Inc., 2007)'
_computing_data_reduction        'CrystalClear (Rigaku Inc., 2007)'
_computing_molecular_graphics    'Olex2 ver 1.1'
_computing_publication_material  'SHELX97 (Sheldrick, 2008)'
_computing_structure_refinement  'Olex2 ver 1.1'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'Saturn724+ CCD'
_diffrn_measurement_method       '\w scans at fixed \c = 45\%'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0419
_diffrn_reflns_av_sigmaI/netI    0.0339
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       26
_diffrn_reflns_limit_l_min       -22
_diffrn_reflns_number            7441
_diffrn_reflns_theta_full        27.46
_diffrn_reflns_theta_max         27.46
_diffrn_reflns_theta_min         2.97
_exptl_absorpt_coefficient_mu    0.108
_exptl_absorpt_correction_T_max  1.0000
_exptl_absorpt_correction_T_min  0.6044
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'CrystalClear (Rigaku Inc., 2007)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.412
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       platelet
_exptl_crystal_F_000             436
_exptl_crystal_size_max          0.50
_exptl_crystal_size_mid          0.38
_exptl_crystal_size_min          0.09
_refine_diff_density_max         0.171
_refine_diff_density_min         -0.160
_refine_diff_density_rms         0.037
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   10(10)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.119
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     272
_refine_ls_number_reflns         2407
_refine_ls_number_restraints     2
_refine_ls_restrained_S_all      1.119
_refine_ls_R_factor_all          0.0498
_refine_ls_R_factor_gt           0.0471
_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^)+(0.0291P)^2^+0.2473P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0973
_refine_ls_wR_factor_ref         0.0992
_reflns_number_gt                2280
_reflns_number_total             2407
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            c3ob00046j.txt
_cod_data_source_block           sa1754
_cod_original_cell_volume        974.7(5)
_cod_original_sg_symbol_H-M      P2(1)
_cod_database_code               7152838