Selective Michael-aldol reaction by use of sterically hindered aluminum aryloxides as Lewis acids: an easy approach to cyclobutane amino acids.
Avenoza, Alberto; Busto, Jesús H; Canal, Noelia; Peregrina, Jesús M; Pérez-Fernández, Marta; Organic letters 7 (2005) 3597–3600; doi:10.1021/ol0514707

data_1506679
_publ_section_title
;
 Selective Michael-aldol reaction by use of sterically hindered aluminum
 aryloxides as Lewis acids: an easy approach to cyclobutane amino acids.
;
_journal_issue                   16
_journal_name_full               'Organic letters'
_journal_page_first              3597
_journal_page_last               3600
_journal_paper_doi               10.1021/ol0514707
_journal_volume                  7
_journal_year                    2005
_chemical_formula_sum            'C20 H27 N O4'
_chemical_formula_weight         345.43
_chemical_name_common            compound10
_chemical_name_systematic
; 
 compound10
;
_space_group_IT_number           18
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  'P 2 2ab'
_symmetry_space_group_name_H-M   'P 21 21 2'
_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                   16.4388(1)
_cell_length_b                   20.2730(16)
_cell_length_c                   5.7205(3)
_cell_measurement_reflns_used    4721
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      20.18
_cell_measurement_theta_min      0.21
_cell_volume                     1906.44(18)
_computing_cell_refinement       'HKL Scalepack (Otwinowski & Minor 1997)'
_computing_data_collection       KappaCCD
_computing_data_reduction        'Denzo and Scalepak (Otwinowski'
_computing_molecular_graphics    ORTEP-III
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      173(2)
_diffrn_measured_fraction_theta_full 0.988
_diffrn_measured_fraction_theta_max 0.988
_diffrn_measurement_device_type  KappaCCD
_diffrn_measurement_method       CCD
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'normal-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.1020
_diffrn_reflns_av_sigmaI/netI    0.0910
_diffrn_reflns_limit_h_max       15
_diffrn_reflns_limit_h_min       -15
_diffrn_reflns_limit_k_max       19
_diffrn_reflns_limit_k_min       -19
_diffrn_reflns_limit_l_max       5
_diffrn_reflns_limit_l_min       -5
_diffrn_reflns_number            6315
_diffrn_reflns_theta_full        20.18
_diffrn_reflns_theta_max         20.18
_diffrn_reflns_theta_min         1.24
_exptl_absorpt_coefficient_mu    0.083
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.204
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Neddle
_exptl_crystal_F_000             744
_exptl_crystal_size_max          0.25
_exptl_crystal_size_mid          0.075
_exptl_crystal_size_min          0.05
_refine_diff_density_max         0.218
_refine_diff_density_min         -0.213
_refine_diff_density_rms         0.054
_refine_ls_abs_structure_details 'Flack H D (1983), Acta Cryst. A39, 876-881'
_refine_ls_abs_structure_Flack   3(4)
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.050
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     226
_refine_ls_number_reflns         1803
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.050
_refine_ls_R_factor_all          0.0895
_refine_ls_R_factor_gt           0.0600
_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^)+(0.0790P)^2^+0.3101P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1371
_refine_ls_wR_factor_ref         0.1543
_reflns_number_gt                1349
_reflns_number_total             1803
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol0514707si20050623_120238.cif
_cod_data_source_block           shelxl
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Orthorhombic' changed to
'orthorhombic' according to
/home/saulius/struct/CIF-dictionaries/cif_core.dic dictionary named
'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_cell_volume        1906.4(2)
_cod_original_formula_sum        'C20 H27 N1 O4'
_cod_database_code               1506679