Methyl 2,3,4-Tri-<i>O</i>-benzyl-α-<scp>d</scp>-glucopyranosyl-Derived γ-Silyloxy Allylic Stannanes as Reagents for S<sub>E</sub>2‘ Additions to Aldehydes
作者:James A. Marshall、L. Michelle Elliott
DOI:10.1021/jo9601627
日期:1996.1.1
the derived enolate with TBSCl. The major stannane, 3.1, underwent BF(3)-promoted addition to 2-nonynal to afford a single syn adduct 4.1 in 70-90% yield. The minor stannane, 3.2, gave rise to a 70:30 mixture of adduct 4.1 and the diastereomeric syn adduct 5.1 under these conditions. The stereochemistry of the adduct 4.1 was proven by degradation of the bis-TBS derivative 4.2 to aldehyde 4.3, prepared
由3-(5-吡喃基)-2-丙烯醛2.1和铜酸盐Bu(3)Sn(Bu)CuCNLi(2)制备甲基α-D-吡喃葡萄糖苷烯丙基锡烷3.1和3.2用TBSC1烯醇化。主要的锡烷3.1,经过BF(3)促进的除2-壬醛外的加成反应,以70-90%的产率提供了一个单一的加合物4.1。在这些条件下,次要的锡烷3.2产生加合物4.1和非对映异构体加合物5.1的70:30混合物。通过将双-TBS衍生物4.2降解为醛4.3证明了加合物4.1的立体化学,该醛是由(R,Z)-γ-OTBS巴豆基锡烷4.4和2-壬醛按照相似的路线独立制备的。加合物4.1和5.1的类似降解导致ca降低。65:35醛4.3及其对映异构体的混合物。因此,可以推测添加了锡烷3。2至2-非清合主要通过syn S(E)2'途径发生。BF(3)促进的enal 6.1的添加按预期进行。锡烷3.1以87-97%的产率提供了顺式加合物6.2,而锡烷3.2