Design, development, mechanistic elucidation, and rational optimization of a tandem ireland claisen/cope rearrangement reaction for rapid access to the (iso)cyclocitrinol core.
Plummer, Christopher W.; Wei, Carolyn S.; Yozwiak, Carrie E.; Soheili, Arash; Smithback, Sara O.; Leighton, James L.; Journal of the American Chemical Society 136 (2014) 9878–9881; doi:10.1021/ja505131v

data_4122140
_publ_section_title
;
 Design, development, mechanistic elucidation, and rational optimization
 of a tandem ireland claisen/cope rearrangement reaction for rapid access
 to the (iso)cyclocitrinol core.
;
_journal_issue                   28
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              9878
_journal_page_last               9881
_journal_paper_doi               10.1021/ja505131v
_journal_volume                  136
_journal_year                    2014
_chemical_absolute_configuration unk
_chemical_formula_sum            'C20 H28 O3'
_chemical_formula_weight         316.42
_space_group_IT_number           5
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'C 2y'
_symmetry_space_group_name_H-M   'C 1 2 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                 110.666(4)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   18.803(5)
_cell_length_b                   6.1937(15)
_cell_length_c                   16.084(4)
_cell_measurement_reflns_used    2998
_cell_measurement_temperature    125(2)
_cell_measurement_theta_max      28.34
_cell_measurement_theta_min      2.23
_cell_volume                     1752.6(8)
_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 1.000
_diffrn_measured_fraction_theta_max 1.000
_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  0.0863
_diffrn_reflns_av_sigmaI/netI    0.0676
_diffrn_reflns_limit_h_max       24
_diffrn_reflns_limit_h_min       -24
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       -21
_diffrn_reflns_number            12131
_diffrn_reflns_theta_full        28.28
_diffrn_reflns_theta_max         28.28
_diffrn_reflns_theta_min         1.35
_exptl_absorpt_coefficient_mu    0.079
_exptl_absorpt_correction_T_max  0.9984
_exptl_absorpt_correction_T_min  0.9737
_exptl_absorpt_correction_type   empirical
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            COLORLESS
_exptl_crystal_density_diffrn    1.199
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       NEEDLE
_exptl_crystal_F_000             688
_exptl_crystal_size_max          0.34
_exptl_crystal_size_mid          0.05
_exptl_crystal_size_min          0.02
_refine_diff_density_max         0.341
_refine_diff_density_min         -0.266
_refine_diff_density_rms         0.062
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.033
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     210
_refine_ls_number_reflns         2378
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.033
_refine_ls_R_factor_all          0.0929
_refine_ls_R_factor_gt           0.0566
_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^)+(0.0821P)^2^+0.0873P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1290
_refine_ls_wR_factor_ref         0.1479
_reflns_number_gt                1685
_reflns_number_total             2378
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ja505131v_si_003.cif
_cod_data_source_block           cp12s10
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to
/usr/data/users/saulius/crontab/automatic-downloads/rss-feeds/ACS/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from
2011-04-26.

'_exptl_absorpt_correction_type' value 'EMPIRICAL'
changed to 'empirical' according to
/usr/data/users/saulius/crontab/automatic-downloads/rss-feeds/ACS/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from
2011-04-26.

'_refine_ls_hydrogen_treatment' value 'CONSTR' changed
to 'constr' according to
/usr/data/users/saulius/crontab/automatic-downloads/rss-feeds/ACS/lib/dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 2281 2013-09-26 08:29:07Z andrius 

 Adding full bibliography for 4122140--4122141.cif.
;
_cod_original_cell_volume        1752.7(7)
_cod_original_sg_symbol_H-M      C2
_cod_database_code               4122140