Ring fission of chiral cyclic acetals plus intramolecular [4 + 2] cycloaddition: a sequential access to medium-size lactones. Application to the synthesis of carbasugars.
Lemiègre, Loïc; Stevens, Richard L.; Combret, Jean-Claude; Maddaluno, Jacques; Organic & biomolecular chemistry 3 (2005) 1308–1318; doi:10.1039/b419381d

data_7150062
_publ_section_title
;
 Ring fission of chiral cyclic acetals plus intramolecular [4 + 2]
 cycloaddition: a sequential access to medium-size lactones.
 Application to the synthesis of carbasugars.
;
_journal_issue                   7
_journal_name_full               'Organic &amp; biomolecular chemistry'
_journal_page_first              1308
_journal_page_last               1318
_journal_paper_doi               10.1039/b419381d
_journal_volume                  3
_journal_year                    2005
_chemical_formula_moiety         'C18 H22 O4'
_chemical_formula_sum            'C18 H22 O4'
_chemical_formula_weight         302.36
_chemical_name_common
;
2-hydroxy-3,6,11-trimethyl-1,2,4a,13a-tetrahydro-5,12-dioxa-
dibenzo(a,e)cyclo-nonan-13-one
;
_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   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 95.1590(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            8
_cell_length_a                   10.0036(7)
_cell_length_b                   27.0011(18)
_cell_length_c                   12.1811(8)
_cell_measurement_temperature    296(2)
_cell_volume                     3276.9(4)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      296(2)
_diffrn_measured_fraction_theta_full 0.997
_diffrn_measured_fraction_theta_max 0.997
_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  0.0224
_diffrn_reflns_av_sigmaI/netI    0.0366
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_h_min       -12
_diffrn_reflns_limit_k_max       33
_diffrn_reflns_limit_k_min       -33
_diffrn_reflns_limit_l_max       15
_diffrn_reflns_limit_l_min       -15
_diffrn_reflns_number            26441
_diffrn_reflns_theta_full        26.41
_diffrn_reflns_theta_max         26.41
_diffrn_reflns_theta_min         1.84
_exptl_absorpt_coefficient_mu    0.086
_exptl_absorpt_correction_T_max  1.000000
_exptl_absorpt_correction_T_min  0.744898
_exptl_absorpt_correction_type   empirical
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.226
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Prismatic
_exptl_crystal_F_000             1296
_exptl_crystal_size_max          1.60
_exptl_crystal_size_mid          0.67
_exptl_crystal_size_min          0.35
_refine_diff_density_max         0.144
_refine_diff_density_min         -0.164
_refine_diff_density_rms         0.027
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   0.3(6)
_refine_ls_extinction_coef       0.0008(3)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   1.035
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     1146
_refine_ls_number_reflns         13096
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      1.035
_refine_ls_R_factor_all          0.0581
_refine_ls_R_factor_gt           0.0450
_refine_ls_shift/su_max          0.087
_refine_ls_shift/su_mean         0.005
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0394P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0854
_refine_ls_wR_factor_ref         0.0901
_reflns_number_gt                10487
_reflns_number_total             13096
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b419381d.txt
_cod_data_source_block           ll478m
_cod_original_sg_symbol_H-M      P21
_cod_database_code               7150062