A macrocyclic β-iodoallenolate intermediate is key: synthesis of the ABD core of phomactin A.
Ciesielski, Jennifer; Cariou, Kevin; Frontier, Alison J.; Organic letters 14 (2012) 4082–4085; doi:10.1021/ol3017116

data_1556124
_publ_section_title
;
 A macrocyclic \b-iodoallenolate intermediate is key: synthesis of the ABD
 core of phomactin A.
;
_journal_issue                   16
_journal_name_full               'Organic letters'
_journal_page_first              4082
_journal_page_last               4085
_journal_paper_doi               10.1021/ol3017116
_journal_volume                  14
_journal_year                    2012
_chemical_absolute_configuration ad
_chemical_formula_moiety         'C26 H30 I N O5'
_chemical_formula_sum            'C26 H30 I N O5'
_chemical_formula_weight         563.41
_chemical_name_common            frojc02
_space_group_IT_number           19
_space_group_name_Hall           'P 2ac 2ab'
_space_group_name_H-M_alt        'P 21 21 21'
_symmetry_cell_setting           orthorhombic
_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                   7.7887(16)
_cell_length_b                   14.737(3)
_cell_length_c                   21.142(4)
_cell_measurement_reflns_used    3779
_cell_measurement_temperature    100.0(1)
_cell_measurement_theta_max      35.74
_cell_measurement_theta_min      2.37
_cell_volume                     2426.7(8)
_computing_cell_refinement       'SAINT (Bruker, 2009)'
_computing_data_collection       'APEX2 (Bruker, 2009)'
_computing_data_reduction        'SAINT (Bruker, 2009)'
_computing_molecular_graphics    'SHELXTL (Sheldrick, 2008)'
_computing_publication_material  'SHELXTL (Sheldrick, 2008)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 2008)'
_computing_structure_solution    'SIR97 (Altomare et al., 1999)'
_diffrn_ambient_temperature      100.0(1)
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Bruker SMART APEX II CCD Platform'
_diffrn_measurement_method       'area detector, \w scans per \f'
_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  0.0640
_diffrn_reflns_av_sigmaI/netI    0.0563
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       25
_diffrn_reflns_limit_k_min       -25
_diffrn_reflns_limit_l_max       36
_diffrn_reflns_limit_l_min       -36
_diffrn_reflns_number            59592
_diffrn_reflns_theta_full        37.78
_diffrn_reflns_theta_max         37.78
_diffrn_reflns_theta_min         1.68
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    1.356
_exptl_absorpt_correction_T_max  0.9230
_exptl_absorpt_correction_T_min  0.6482
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   'SADABS (Sheldrick, 2008)'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.542
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             1144
_exptl_crystal_size_max          0.35
_exptl_crystal_size_mid          0.12
_exptl_crystal_size_min          0.06
_refine_diff_density_max         1.165
_refine_diff_density_min         -0.700
_refine_diff_density_rms         0.103
_refine_ls_abs_structure_details
'Flack H D (1983), 5802 Friedel pairs, Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   -0.018(12)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   0.995
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     302
_refine_ls_number_reflns         12987
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      0.995
_refine_ls_R_factor_all          0.0672
_refine_ls_R_factor_gt           0.0418
_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^)+(0.0390P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0783
_refine_ls_wR_factor_ref         0.0870
_reflns_number_gt                9590
_reflns_number_total             12987
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol3017116_si_004.cif
_cod_data_source_block           frojc02
_cod_original_cell_volume        2426.8(9)
_cod_database_code               1556124