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_4102855
_publ_section_title
;
 Cyclobutenone as a Highly Reactive Dienophile: Expanding Upon Diels-Alder
 Paradigms
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_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_absolute_configuration unk
_chemical_formula_sum            'C8 H8 O2'
_chemical_formula_weight         136.14
_space_group_IT_number           19
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2ac 2ab'
_symmetry_space_group_name_H-M   'P 21 21 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                   6.9460(6)
_cell_length_b                   8.9632(8)
_cell_length_c                   10.3522(9)
_cell_measurement_reflns_used    8266
_cell_measurement_temperature    125(2)
_cell_measurement_theta_max      32.57
_cell_measurement_theta_min      2.27
_cell_volume                     644.51(10)
_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 0.975
_diffrn_measured_fraction_theta_max 0.975
_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  0.0249
_diffrn_reflns_av_sigmaI/netI    0.0194
_diffrn_reflns_limit_h_max       10
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            11125
_diffrn_reflns_theta_full        32.68
_diffrn_reflns_theta_max         32.68
_diffrn_reflns_theta_min         3.01
_exptl_absorpt_coefficient_mu    0.101
_exptl_absorpt_correction_T_max  0.9950
_exptl_absorpt_correction_T_min  0.9637
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            COLORLESS
_exptl_crystal_density_diffrn    1.403
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       BLOCK
_exptl_crystal_F_000             288
_exptl_crystal_size_max          0.37
_exptl_crystal_size_mid          0.18
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.423
_refine_diff_density_min         -0.229
_refine_diff_density_rms         0.049
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.069
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     91
_refine_ls_number_reflns         2272
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.069
_refine_ls_R_factor_all          0.0368
_refine_ls_R_factor_gt           0.0347
_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^)+(0.0572P)^2^+0.0796P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0911
_refine_ls_wR_factor_ref         0.0933
_reflns_number_gt                2174
_reflns_number_total             2272
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja1056888_si_002.cif
_cod_data_source_block           xxws10
_cod_depositor_comments
;
The following automatic conversions were performed:

'_chemical_absolute_configuration' value 'UNK' changed to 'unk'
according to the built-in table from CIF Core dictionary named
'cif_core.dic' version 2.4.1 from
2010-06-29.

'_exptl_absorpt_correction_type' value 'EMPIRICAL'
changed to 'empirical' according to the built-in table from CIF Core
dictionary named 'cif_core.dic' version 2.4.1 from
2010-06-29.

'_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               4102855