A practical synthesis of (+/-)-alpha-isosparteine from a tetraoxobispidine core.
Blakemore, Paul R.; Kilner, Colin; Norcross, Neil R.; Astles, Peter C.; Organic letters 7 (2005) 4721–4724; doi:10.1021/ol0519184

data_1506721
_publ_section_title
;
 A practical synthesis of (+/-)-alpha-isosparteine from a
 tetraoxobispidine core.
;
_journal_issue                   21
_journal_name_full               'Organic letters'
_journal_page_first              4721
_journal_page_last               4724
_journal_paper_doi               10.1021/ol0519184
_journal_volume                  7
_journal_year                    2005
_chemical_formula_moiety         'C13 H14 N2 O4'
_chemical_formula_sum            'C13 H14 N2 O4'
_chemical_formula_weight         262.26
_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
_cell_angle_beta                 108.0710(13)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   7.05500(10)
_cell_length_b                   18.6760(5)
_cell_length_c                   9.8130(2)
_cell_measurement_reflns_used    9014
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      27.48
_cell_measurement_theta_min      1.00
_cell_volume                     1229.18(5)
_computing_cell_refinement       'DENZO-SMN (Otwinowski & Minor, 1996)'
_computing_data_collection       COLLECT
_computing_data_reduction
'DENZO-SMN and COLLECT (Otwinowski & Minor, 1996)'
_computing_molecular_graphics    ORTEP-III
_computing_publication_material  'local program'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1999)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1986)'
_diffrn_ambient_temperature      150(2)
_diffrn_detector_area_resol_mean 9
_diffrn_measured_fraction_theta_full 0.998
_diffrn_measured_fraction_theta_max 0.998
_diffrn_measurement_device_type  'Nonius KappaCCD area-detector diffractometer'
_diffrn_measurement_method       'phi-omega scans'
_diffrn_radiation_detector       'CCD plate'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_source         'Fine-focus Sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0778
_diffrn_reflns_av_sigmaI/netI    0.0408
_diffrn_reflns_limit_h_max       8
_diffrn_reflns_limit_h_min       -8
_diffrn_reflns_limit_k_max       23
_diffrn_reflns_limit_k_min       -23
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            17730
_diffrn_reflns_theta_full        26.00
_diffrn_reflns_theta_max         26.00
_diffrn_reflns_theta_min         3.09
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.107
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.417
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             552
_exptl_crystal_size_max          0.27
_exptl_crystal_size_mid          0.16
_exptl_crystal_size_min          0.16
_refine_diff_density_max         0.315
_refine_diff_density_min         -0.402
_refine_diff_density_rms         0.104
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.039
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     172
_refine_ls_number_reflns         2403
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.039
_refine_ls_R_factor_all          0.0631
_refine_ls_R_factor_gt           0.0434
_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^)+(0.0659P)^2^+0.3610P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1113
_refine_ls_wR_factor_ref         0.1243
_reflns_number_gt                1849
_reflns_number_total             2403
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol0519184si20050809_053137.cif
_cod_data_source_block           cmpd7
_cod_original_sg_symbol_H-M      P21/c
_cod_database_code               1506721