Stereoselective synthesis of spirocyclic ketones by Nazarov reaction.
Prandi, Cristina; Deagostino, Annamaria; Venturello, Paolo; Occhiato, Ernesto G.; Organic letters 7 (2005) 4345–4348; doi:10.1021/ol051464a

data_1506676
_publ_section_title
;
 Stereoselective synthesis of spirocyclic ketones by Nazarov reaction.
;
_journal_issue                   20
_journal_name_full               'Organic letters'
_journal_page_first              4345
_journal_page_last               4348
_journal_paper_doi               10.1021/ol051464a
_journal_volume                  7
_journal_year                    2005
_chemical_formula_sum            'C13 H18 O2'
_chemical_formula_weight         206
_chemical_name_systematic        4,4,7-trimethyl-6-oxaspiro[4.5]dec-2-en-1-one
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      14
_symmetry_space_group_name_Hall  '-P 2yab'
_symmetry_space_group_name_H-M   'P 1 21/a 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                 107.3(5)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   13.38(5)
_cell_length_b                   6.27(9)
_cell_length_c                   13.70(0)
_cell_measurement_temperature    100
_cell_volume                     1097(17)
_computing_cell_refinement       'CrysAlis RED 1.171.26 (OXford Diffraction)'
_computing_data_collection       'CrysAlis CCD 1.171.26 (OXford Diffraction)'
_computing_data_reduction        'CrysAlis RED 1.171.26 (OXford Diffraction)'
_computing_molecular_graphics
'ORTEP3 for Windows  (Farrugia, L. J., 1997) '
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'Sir2004 (Burla, 2005)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.938
_diffrn_measured_fraction_theta_max 0.938
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_probe          x-ray
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0405
_diffrn_reflns_av_sigmaI/netI    0.0437
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -18
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       17
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            7405
_diffrn_reflns_theta_full        29.43
_diffrn_reflns_theta_max         29.43
_diffrn_reflns_theta_min         4.45
_diffrn_source                   'fine-focus sealed tube'
_diffrn_source_type              'Xcalibur (Oxford Diffraction)  '
_exptl_absorpt_coefficient_mu    0.057
_exptl_absorpt_correction_T_max  1.3134
_exptl_absorpt_correction_T_min  0.9262
_exptl_absorpt_correction_type
;
  'SADABS: Area-Detector
 Absorption Correction. (1996)'
;
_exptl_crystal_colour            'Colorless '
_exptl_crystal_density_diffrn    0.799
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             296
_exptl_crystal_size_max          0.5
_exptl_crystal_size_mid          0.4
_exptl_crystal_size_min          0.1
_refine_diff_density_max         0.309
_refine_diff_density_min         -0.247
_refine_diff_density_rms         0.055
_refine_ls_extinction_coef       0.000(3)
_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   1.072
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     200
_refine_ls_number_reflns         2856
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.072
_refine_ls_R_factor_all          0.0965
_refine_ls_R_factor_gt           0.0638
_refine_ls_shift/su_max          1.032
_refine_ls_shift/su_mean         0.007
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0495P)^2^+0.9497P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1319
_refine_ls_wR_factor_ref         0.1517
_reflns_number_gt                2048
_reflns_number_total             2856
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol051464asi20050623_024658.cif
_cod_data_source_block           cri2_lt
_cod_original_cell_volume        1099.0
_cod_original_sg_symbol_H-M      'P 21/a'
_cod_database_code               1506676