N-heterocyclic carbene catalyzed reaction of enals and 1,2-dicarbonyl compounds: stereoselective synthesis of spiro gamma-butyrolactones.
Nair, Vijay; Vellalath, Sreekumar; Poonoth, Manojkumar; Mohan, Resmi; Suresh, Eringathodi; Organic letters 8 (2006) 507–509; doi:10.1021/ol052926n

data_1505847
_publ_section_title
;
 N-heterocyclic carbene catalyzed reaction of enals and 1,2-dicarbonyl
 compounds: stereoselective synthesis of spiro gamma-butyrolactones.
;
_journal_issue                   3
_journal_name_full               'Organic letters'
_journal_page_first              507
_journal_page_last               509
_journal_paper_doi               10.1021/ol052926n
_journal_volume                  8
_journal_year                    2006
_chemical_formula_sum            'C16 H18 O4'
_chemical_formula_weight         274.30
_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                90.00
_cell_angle_beta                 109.245(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   10.3385(17)
_cell_length_b                   15.144(3)
_cell_length_c                   9.3743(15)
_cell_measurement_temperature    296(2)
_cell_volume                     1385.7(4)
_computing_cell_refinement       'BRUKER SMART'
_computing_data_collection       'BRUKER SMART'
_computing_data_reduction        'BRUKER SAINT'
_computing_molecular_graphics    'ORTEP, PLATON'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.888
_diffrn_measured_fraction_theta_max 0.888
_diffrn_measurement_device_type  'BRUKER SMART APEX CCD DIFFRACTOMETER'
_diffrn_measurement_method       'OMEGA-PHI SCAN'
_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  0.0207
_diffrn_reflns_av_sigmaI/netI    0.0298
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            8068
_diffrn_reflns_theta_full        28.29
_diffrn_reflns_theta_max         28.29
_diffrn_reflns_theta_min         2.09
_exptl_absorpt_coefficient_mu    0.094
_exptl_crystal_colour            COLOURLESS
_exptl_crystal_density_diffrn    1.315
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       BLOCKS
_exptl_crystal_F_000             584
_exptl_crystal_size_max          0.34
_exptl_crystal_size_mid          0.26
_exptl_crystal_size_min          0.20
_refine_diff_density_max         0.278
_refine_diff_density_min         -0.205
_refine_diff_density_rms         0.040
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.109
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     182
_refine_ls_number_reflns         3177
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.109
_refine_ls_R_factor_all          0.0791
_refine_ls_R_factor_gt           0.0638
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0607P)^2^+0.4570P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1432
_refine_ls_wR_factor_ref         0.1511
_reflns_number_gt                2544
_reflns_number_total             3177
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol052926nsi20051202_043216.cif
_cod_data_source_block           vijay9nf
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 

The following automatic conversions were performed:

'_refine_ls_weighting_scheme' value 'calc
w=1/[\s^2^(Fo^2^)+(0.0607P)^2^+0.4570P] where P=(Fo^2^+2Fc^2^)/3' was
changed to 'calc'. New tag '_refine_ls_weighting_details' was
created. The value of the new tag was set to
'w=1/[\s^2^(Fo^2^)+(0.0607P)^2^+0.4570P] where P=(Fo^2^+2Fc^2^)/3'.

Automatic conversion script
Id: cif_fix_values 3143 2015-03-26 13:38:13Z robertas 
;
_cod_original_sg_symbol_H-M      P21/c
_cod_database_code               1505847