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_1506677
_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            'C14 H23 N O4'
_chemical_formula_weight         269.33
_chemical_name_common            cyclohexil
_chemical_name_systematic        cyclohexil
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_Int_Tables_number      14
_symmetry_space_group_name_Hall  '-P 2ybc'
_symmetry_space_group_name_H-M   'P 1 21/c 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                 115.5278(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   9.4901(10)
_cell_length_b                   17.1409(3)
_cell_length_c                   9.9187(2)
_cell_measurement_reflns_used    7787
_cell_measurement_temperature    173(2)
_cell_measurement_theta_max      21.97
_cell_measurement_theta_min      0.21
_cell_volume                     1455.95(16)
_computing_cell_refinement       'HKL Scalepack (Otwinowski & Minor 1997)'
_computing_data_collection       KappaCCD
_computing_data_reduction        'Denzo and Scalepak (Otwinowski 1997'
_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 0.983
_diffrn_measured_fraction_theta_max 0.983
_diffrn_measurement_device_type  KappaCCD
_diffrn_measurement_method       CCD
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0422
_diffrn_reflns_av_sigmaI/netI    0.0238
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -9
_diffrn_reflns_limit_k_max       18
_diffrn_reflns_limit_k_min       -18
_diffrn_reflns_limit_l_max       10
_diffrn_reflns_limit_l_min       -10
_diffrn_reflns_number            11926
_diffrn_reflns_theta_full        21.97
_diffrn_reflns_theta_max         21.97
_diffrn_reflns_theta_min         1.19
_diffrn_source                   'normal-focus sealed tube'
_exptl_absorpt_coefficient_mu    0.089
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            Colourless
_exptl_crystal_density_diffrn    1.229
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       Prism
_exptl_crystal_F_000             584
_exptl_crystal_size_max          0.50
_exptl_crystal_size_mid          0.37
_exptl_crystal_size_min          0.32
_refine_diff_density_max         0.446
_refine_diff_density_min         -0.432
_refine_diff_density_rms         0.041
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.049
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     172
_refine_ls_number_reflns         1744
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.049
_refine_ls_R_factor_all          0.0504
_refine_ls_R_factor_gt           0.0465
_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^)+(0.0688P)^2^+1.1499P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1241
_refine_ls_wR_factor_ref         0.1278
_reflns_number_gt                1593
_reflns_number_total             1744
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol0514707si20050623_120133.cif
_cod_data_source_block           shelxl
_cod_original_cell_volume        1455.95(4)
_cod_original_sg_symbol_H-M      P21/c
_cod_original_formula_sum        'C14 H23 N1 O4'
_cod_database_code               1506677