Reversibility in the boron-mediated ketone-ketone aldol reaction.
Cergol, Katie M; Jensen, Paul; Turner, Peter; Coster, Mark J; Chemical communications (Cambridge, England)  (2007) 1363–1365; doi:10.1039/b617094c

data_7101811
_publ_section_title
;
 Reversibility in the boron-mediated ketone-ketone aldol reaction.
;
_journal_issue                   13
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              1363
_journal_page_last               1365
_journal_paper_doi               10.1039/b617094c
_journal_year                    2007
_chemical_formula_sum            'C20 H36 O2'
_chemical_formula_weight         308.49
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      14
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 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                 96.953(1)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   11.9035(3)
_cell_length_b                   12.7978(4)
_cell_length_c                   24.8807(7)
_cell_measurement_reflns_used    6953
_cell_measurement_temperature    150(2)
_cell_measurement_theta_max      26.909
_cell_measurement_theta_min      2.942
_cell_volume                     3762.4(2)
_computing_cell_refinement       'SAINT (Bruker-Nonius,2003)'
_computing_data_collection       'APEX (Bruker-Nonius,2003)'
_computing_data_reduction        'SAINT and XPREP (Bruker-Nonius 2003)'
_computing_molecular_graphics
;
xtal 3.6 (Hall,du Boulay, D.J. & Olthof-Hazekamp, R. 1999)
ORTEPII (Johnson,C.K., 1976).
WinGX (Farrugia, 1999)
;
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SIR97 (Altomare, et. al. 1997)'
_diffrn_ambient_temperature      150(2)
_diffrn_crystal_treatment
;
attached with Exxon Paratone N, to a short length
of fibre supported on a thin piece of copper wire
inserted in a copper mounting pin. The crystal was
quenched in a cold nitrogen gas stream from an
Oxford Cryosystems Cryostream.
;
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_diffrn_measurement_device_type  APEXII-FR591
_diffrn_measurement_method       \w+\f
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'rotating anode'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0696
_diffrn_reflns_av_sigmaI/netI    0.0736
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -16
_diffrn_reflns_limit_k_max       17
_diffrn_reflns_limit_k_min       -17
_diffrn_reflns_limit_l_max       34
_diffrn_reflns_limit_l_min       -34
_diffrn_reflns_number            80737
_diffrn_reflns_theta_full        29.12
_diffrn_reflns_theta_max         29.12
_diffrn_reflns_theta_min         1.82
_diffrn_standards_decay_%        0
_diffrn_standards_interval_count 0
_diffrn_standards_interval_time  0
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.068
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.089
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             1376
_exptl_crystal_size_max          0.200
_exptl_crystal_size_mid          0.179
_exptl_crystal_size_min          0.122
_refine_diff_density_max         0.264
_refine_diff_density_min         -0.273
_refine_diff_density_rms         0.042
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.242
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     411
_refine_ls_number_reflns         10076
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.242
_refine_ls_R_factor_all          0.0819
_refine_ls_R_factor_gt           0.0447
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.02P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0825
_refine_ls_wR_factor_ref         0.0848
_reflns_number_gt                5389
_reflns_number_total             10076
_reflns_threshold_expression     I>2\s(I)
_cod_data_source_file            b617094c.txt
_cod_data_source_block           mc05pt1
_cod_original_sg_symbol_H-M      'P 21/n '
_cod_database_code               7101811