Diverging Pathways to Topologically Complex Polycyclic Bis-acetals and Their Ring System Interchange.
Castillo, Rafael R.; Aquino, Maurizio; Gandara, Zoila; Safir, Imad; Elkhayat, Zobida; Retailleau, Pascal; Arseniyadis, Siméon; Organic letters 14 (2012) 1628–1631; doi:10.1021/ol300388b

data_1507200
_publ_section_title
;
 Diverging Pathways to Topologically Complex Polycyclic Bis-acetals and
 Their Ring System Interchange.
;
_journal_issue                   6
_journal_name_full               'Organic letters'
_journal_page_first              1628
_journal_page_last               1631
_journal_paper_doi               10.1021/ol300388b
_journal_volume                  14
_journal_year                    2012
_chemical_absolute_configuration syn
_chemical_formula_moiety         'C18 H22 O3'
_chemical_formula_sum            'C18 H22 O3'
_chemical_formula_weight         286.36
_chemical_name_systematic
; 
 (4aR,9R,9aR)-7-methoxy-1,2,3,4,9,10-hexahydro-4a,9a-
(epoxyethano)-9,10-(epoxymethano)anthracene
;
_space_group_IT_number           4
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  'P 2yb'
_symmetry_space_group_name_H-M   'P 1 21 1'
_atom_sites_solution_hydrogens   difmap
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 104.222(6)
_cell_angle_gamma                90.00
_cell_formula_units_Z            2
_cell_length_a                   7.3848(5)
_cell_length_b                   7.8147(7)
_cell_length_c                   12.8239(3)
_cell_measurement_temperature    293(2)
_cell_volume                     717.38(8)
_computing_cell_refinement       'Dirax/lsq (Duisenberg & Schreurs, 1989-2000)'
_computing_data_collection       'Collect (Bruker AXS BV, 1997-2004)'
_computing_data_reduction        'EvalCCD (Duisenberg & Schreurs 1990-2000)'
_computing_molecular_graphics    'PLATON (Spek, 2003)'
_computing_publication_material  'SHELXL97 (Sheldrick, 2008)'
_computing_structure_refinement
'SHELXL97 (Sheldrick, 2008); CRYSTALBUILDER (Welter, 2006)'
_computing_structure_solution    'SIR92 (Giacovazzo et al, 1993)'
_diffrn_ambient_temperature      293(2)
_diffrn_measured_fraction_theta_full 0.995
_diffrn_measured_fraction_theta_max 0.995
_diffrn_measurement_device_type  'Nonius kappa-CCD diffractometer'
_diffrn_measurement_method       'phi and omega 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  0.0306
_diffrn_reflns_av_sigmaI/netI    0.0316
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -10
_diffrn_reflns_limit_k_max       10
_diffrn_reflns_limit_k_min       -10
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            10254
_diffrn_reflns_reduction_process
;
 Scaled and merged with Sortav
 R.H. Blessing, (1987) Cryst. Rev. 1, 3-58
 R.H. Blessing, (1989) J. Appl. Cryst. 22, 396-397
;
_diffrn_reflns_theta_full        30.00
_diffrn_reflns_theta_max         30.00
_diffrn_reflns_theta_min         3.78
_exptl_absorpt_coefficient_mu    0.089
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colourless
_exptl_crystal_density_diffrn    1.326
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             308
_exptl_crystal_size_max          0.60
_exptl_crystal_size_mid          0.32
_exptl_crystal_size_min          0.16
_refine_diff_density_max         0.278
_refine_diff_density_min         -0.183
_refine_diff_density_rms         0.042
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.046
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     191
_refine_ls_number_reflns         2223
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.045
_refine_ls_R_factor_all          0.0520
_refine_ls_R_factor_gt           0.0389
_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^)+(0.0586P)^2^+0.0925P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0940
_refine_ls_wR_factor_ref         0.0997
_reflns_number_gt                1874
_reflns_number_total             2223
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol300388b_si_003.cif
_cod_data_source_block           compound_5b
_cod_original_cell_volume        717.39(8)
_cod_original_sg_symbol_H-M      P21
_cod_database_code               1507200