Strained to the limit: when a cyclobutyl moiety becomes a thermodynamic sink in a protolytic ring-opening of photogenerated oxetanes.
Valiulin, Roman A.; Arisco, Teresa M.; Kutateladze, Andrei G.; Organic letters 12 (2010) 3398–3401; doi:10.1021/ol101297b

data_1503101
_publ_section_title
;
 Strained to the limit: when a cyclobutyl moiety becomes a thermodynamic
 sink in a protolytic ring-opening of photogenerated oxetanes.
;
_journal_issue                   15
_journal_name_full               'Organic letters'
_journal_page_first              3398
_journal_page_last               3401
_journal_paper_doi               10.1021/ol101297b
_journal_volume                  12
_journal_year                    2010
_chemical_formula_moiety         'C18 H22 O1.50'
_chemical_formula_sum            'C18 H22 O1.5'
_chemical_formula_weight         262.36
_chemical_name_common            spirohemiacetal
_chemical_name_systematic
;
spiro[13-hydroxy-3,12-dioxatetracyclo[5.2.2^5,8^.0^5,6^]tridecane-
4,5'-bicyclo[2.2.2]oct[2]ene]
;
_space_group_IT_number           2
_symmetry_cell_setting           triclinic
_symmetry_space_group_name_Hall  '-P 1'
_symmetry_space_group_name_H-M   'P -1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                79.4580(10)
_cell_angle_beta                 81.7370(10)
_cell_angle_gamma                77.0690(10)
_cell_formula_units_Z            2
_cell_length_a                   6.30570(10)
_cell_length_b                   10.07010(10)
_cell_length_c                   11.39970(10)
_cell_measurement_reflns_used    9859
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      28.38
_cell_measurement_theta_min      2.56
_cell_volume                     689.603(15)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_detector_area_resol_mean 8.33
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker D8 APEX II Diffractometer'
_diffrn_measurement_method       '\f and \w 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  0.0212
_diffrn_reflns_av_sigmaI/netI    0.0105
_diffrn_reflns_limit_h_max       7
_diffrn_reflns_limit_h_min       -7
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -12
_diffrn_reflns_limit_l_max       14
_diffrn_reflns_limit_l_min       -14
_diffrn_reflns_number            25557
_diffrn_reflns_theta_full        26.37
_diffrn_reflns_theta_max         26.37
_diffrn_reflns_theta_min         1.83
_exptl_absorpt_coefficient_mu    0.078
_exptl_absorpt_correction_T_max  0.9925
_exptl_absorpt_correction_T_min  0.9625
_exptl_absorpt_correction_type   multi-scan
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.263
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       right
_exptl_crystal_F_000             284
_exptl_crystal_size_max          0.49
_exptl_crystal_size_mid          0.25
_exptl_crystal_size_min          0.10
_refine_diff_density_max         0.363
_refine_diff_density_min         -0.254
_refine_diff_density_rms         0.052
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.614
_refine_ls_hydrogen_treatment    noref
_refine_ls_matrix_type           full
_refine_ls_number_parameters     191
_refine_ls_number_reflns         2824
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.614
_refine_ls_R_factor_all          0.0417
_refine_ls_R_factor_gt           0.0396
_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^)+(0.1318P)^2^+0.7700P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1138
_refine_ls_wR_factor_ref         0.1182
_reflns_number_gt                2639
_reflns_number_total             2824
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol101297b_si_009.cif
_cod_data_source_block           tma25131_fr70_bruce
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Triclinic' changed to 'triclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_cell_volume        689.603(14)
_cod_original_sg_symbol_H-M      'P-1   '
_cod_original_formula_sum        'C18 H22 O1.50'
_cod_database_code               1503101