Asymmetric endoselective [4+2] heterocycloadditions of styrene dienophiles with chiral benzylidenepyruvic esters. Total synthesis of (−)-O-dimethylsugiresinol
作者:Gilles Dujardin、Mickaël Maudet、Eric Brown
DOI:10.1016/s0040-4039(97)00144-5
日期:1997.3
Eu(fod)3 catalyzed [4+2] heterocycloadditions of para-methoxystyrene 7 with esters 8a-f of benzylidenepyruvic acids (deriving from various chiral alcohols) furnished endo adducts 9a-f with variable diastereoselective ratios (from to ). Interestingly, the benzylidenepyruvic esters 8g and 8h, deriving from a new chiral vector, the α-O-silyl ether 6 of (D)-(−)-erythronolactone 5, gave the corresponding
铕(FOD)3催化的[4 + 2]的heterocycloadditions第-methoxystyrene 7与酯8A-F的benzylidenepyruvic酸(来自各种手性醇导出)家具内加合物9A-F具有可变非对映选择性比(从至)。有趣的是,benzylidenepyruvic酯8克和8H,从一个新的手性载体,所述导出α - ø -甲硅烷基醚6( - ) - - (d)的erythronolactone 5,得到相应的内切加合物9克和9H非对映选择性高()的化合物。加合物9h被用作“天然”(-)-二甲基sugiresinol(1b)的五步合成中的前体。