Diastereoselective formal total synthesis of (+/-)-triptolide via a novel cationic cyclization of 2-alkenyl-1,3-dithiolane.
Goncalves, Sylvie; Hellier, Paul; Nicolas, Marc; Wagner, Alain; Baati, Rachid; Chemical communications (Cambridge, England) 46 (2010) 5778–5780; doi:10.1039/c0cc00250j

data_7112906
_publ_section_title
;
 Diastereoselective formal total synthesis of (+/-)-triptolide via a novel
 cationic cyclization of 2-alkenyl-1,3-dithiolane.
;
_journal_issue                   31
_journal_name_full
'Chemical communications (Cambridge, England)'
_journal_page_first              5778
_journal_page_last               5780
_journal_paper_doi               10.1039/c0cc00250j
_journal_volume                  46
_journal_year                    2010
_chemical_formula_moiety         'C19 H26 O2'
_chemical_formula_sum            'C19 H26 O2'
_chemical_formula_weight         286.40
_chemical_name_systematic
;
?
;
_space_group_IT_number           15
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-C 2yc'
_symmetry_space_group_name_H-M   'C 1 2/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                 96.279(2)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   19.4535(11)
_cell_length_b                   7.3089(3)
_cell_length_c                   22.1934(12)
_cell_measurement_reflns_used    13249
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      27.485
_cell_measurement_theta_min      0.998
_cell_volume                     3136.6(3)
_computing_cell_refinement       'Denzo (Nonius B.V., 1998)'
_computing_data_collection       'Collect (Nonius B.V., 1998)'
_computing_data_reduction        'Denzo (Nonius B.V., 1998)'
_computing_molecular_graphics    'PLATON 98 (Spek, 1998)'
_computing_publication_material  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.987
_diffrn_measured_fraction_theta_max 0.987
_diffrn_measurement_device_type  KappaCCD
_diffrn_measurement_method       'phi and omega scans'
_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  0.0424
_diffrn_reflns_av_sigmaI/netI    0.0507
_diffrn_reflns_limit_h_max       19
_diffrn_reflns_limit_h_min       -25
_diffrn_reflns_limit_k_max       9
_diffrn_reflns_limit_k_min       -7
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            9342
_diffrn_reflns_theta_full        27.48
_diffrn_reflns_theta_max         27.48
_diffrn_reflns_theta_min         1.85
_exptl_absorpt_coefficient_mu    0.076
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.213
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1248
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.317
_refine_diff_density_min         -0.258
_refine_diff_density_rms         0.086
_refine_ls_extinction_coef       0.0157(16)
_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   1.043
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     195
_refine_ls_number_reflns         3564
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.043
_refine_ls_R_factor_all          0.0863
_refine_ls_R_factor_gt           0.0518
_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^)+(0.0950P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1322
_refine_ls_wR_factor_ref         0.1587
_reflns_number_gt                2396
_reflns_number_total             3564
_reflns_threshold_expression     I>2sigma(I)
_cod_data_source_file            c0cc00250j.txt
_cod_data_source_block           wagner11
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to
/usr/data/users/saulius/automatic-downloads/retrospective/RSC/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 2281 2013-09-26 08:29:07Z andrius 
;
_cod_original_sg_symbol_H-M      'C 2/c'
_cod_database_code               7112906