Intramolecular nitrone dipolar cycloadditions: control of regioselectivity and synthesis of naturally-occurring spirocyclic alkaloids.
Hodges, Alastair J.; Adams, Joseph P.; Bond, Andrew D.; Holmes, Andrew B.; Press, Neil J.; Roughley, Stephen D.; Ryan, John H.; Saubern, Simon; Smith, Catherine J.; Turnbull, Michael D.; Newton, Annabella F.; Organic & biomolecular chemistry 10 (2012) 8963–8974; doi:10.1039/c2ob26333e

data_7152689
_publ_section_title
;
 Intramolecular nitrone dipolar cycloadditions: control of
 regioselectivity and synthesis of naturally-occurring spirocyclic
 alkaloids.
;
_journal_issue                   45
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              8963
_journal_page_last               8974
_journal_paper_doi               10.1039/c2ob26333e
_journal_volume                  10
_journal_year                    2012
_chemical_absolute_configuration unk
_chemical_formula_moiety         'C11 H16 N2 O'
_chemical_formula_sum            'C11 H16 N2 O'
_chemical_formula_weight         192.26
_space_group_IT_number           29
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2c -2ac'
_symmetry_space_group_name_H-M   'P c a 21'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.6609(9)
_cell_length_b                   11.5354(11)
_cell_length_c                   9.1360(5)
_cell_measurement_reflns_used    3249
_cell_measurement_temperature    180(2)
_cell_measurement_theta_max      25.03
_cell_measurement_theta_min      1.00
_cell_volume                     1018.14(15)
_computing_cell_refinement       'Denzo/Scalepack (Otwinowski & Minor, 1997)'
_computing_data_collection       'Collect (Nonius, 1998)'
_computing_data_reduction        Denzo/Scalepack
_computing_publication_material  SHELXL-97
_computing_structure_refinement  SHELXL-97
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1997)'
_diffrn_ambient_temperature      180(2)
_diffrn_measured_fraction_theta_full 0.991
_diffrn_measured_fraction_theta_max 0.991
_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  0.0974
_diffrn_reflns_av_sigmaI/netI    0.1020
_diffrn_reflns_limit_h_max       11
_diffrn_reflns_limit_h_min       -11
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -9
_diffrn_reflns_number            5693
_diffrn_reflns_theta_full        25.00
_diffrn_reflns_theta_max         25.00
_diffrn_reflns_theta_min         4.57
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.082
_exptl_absorpt_correction_T_max  1.029
_exptl_absorpt_correction_T_min  0.982
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'Sortav (Blessing, 1995)'
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.254
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             416
_exptl_crystal_size_max          0.39
_exptl_crystal_size_mid          0.07
_exptl_crystal_size_min          0.07
_refine_diff_density_max         0.126
_refine_diff_density_min         -0.145
_refine_diff_density_rms         0.034
_refine_ls_abs_structure_details
;
In the absence of significant anomalous scattering effects, the absolute
structure cannot be determined. Friedel pairs have *not* been merged.
;
_refine_ls_extinction_coef       0.032(6)
_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   0.982
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     128
_refine_ls_number_reflns         1705
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.982
_refine_ls_R_factor_all          0.0803
_refine_ls_R_factor_gt           0.0401
_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^)+(0.0377P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0754
_refine_ls_wR_factor_ref         0.0878
_reflns_number_gt                1153
_reflns_number_total             1705
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            c2ob26333e.txt
_cod_data_source_block           ah0125
_cod_database_code               7152689