Cyclobutenone as a Highly Reactive Dienophile: Expanding Upon Diels-Alder Paradigms
Xiaohua Li; Samuel J. Danishefsky; Journal of the American Chemical Society 132 (2010) 11004–11005; doi:10.1021/ja1056888

data_4102856
_publ_section_title
;
 Cyclobutenone as a Highly Reactive Dienophile: Expanding Upon Diels-Alder
 Paradigms
;
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              11004
_journal_page_last               11005
_journal_paper_doi               10.1021/ja1056888
_journal_volume                  132
_journal_year                    2010
_chemical_formula_sum            'C24 H18 O2'
_chemical_formula_weight         338.38
_space_group_IT_number           61
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2ab'
_symmetry_space_group_name_H-M   'P b c a'
_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            8
_cell_length_a                   16.6571(15)
_cell_length_b                   10.4157(9)
_cell_length_c                   19.8332(18)
_cell_measurement_reflns_used    9798
_cell_measurement_temperature    125(2)
_cell_measurement_theta_max      31.48
_cell_measurement_theta_min      2.21
_cell_volume                     3441.0(5)
_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      125(2)
_diffrn_measured_fraction_theta_full 0.994
_diffrn_measured_fraction_theta_max 0.994
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_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  0.0408
_diffrn_reflns_av_sigmaI/netI    0.0221
_diffrn_reflns_limit_h_max       24
_diffrn_reflns_limit_h_min       -24
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -15
_diffrn_reflns_limit_l_max       29
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            54867
_diffrn_reflns_theta_full        31.69
_diffrn_reflns_theta_max         31.69
_diffrn_reflns_theta_min         2.05
_exptl_absorpt_coefficient_mu    0.082
_exptl_absorpt_correction_T_max  0.9846
_exptl_absorpt_correction_T_min  0.9790
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.306
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       block
_exptl_crystal_F_000             1424
_exptl_crystal_size_max          0.26
_exptl_crystal_size_mid          0.24
_exptl_crystal_size_min          0.19
_refine_diff_density_max         0.396
_refine_diff_density_min         -0.425
_refine_diff_density_rms         0.049
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.111
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     239
_refine_ls_number_reflns         5795
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.116
_refine_ls_R_factor_all          0.0635
_refine_ls_R_factor_gt           0.0482
_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^)+(0.0449P)^2^+1.8438P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1174
_refine_ls_wR_factor_ref         0.1254
_reflns_number_gt                4643
_reflns_number_total             5795
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja1056888_si_003.cif
_cod_data_source_block           x1s10
_cod_depositor_comments
;
The following automatic conversions were performed:

'_refine_ls_hydrogen_treatment' value 'CONSTR' changed to 'constr'
according to the built-in table from CIF Core 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 
;
_cod_database_code               4102856