Synthesis of Functionalized γ-Lactone via Sakurai <i>exo</i>-Cyclization/Rearrangement of 3,3-Bis(silyl) Enol Ester with a Tethered Acetal
作者:Zhiping Yin、Zengjin Liu、Zhenggang Huang、Yang Chu、Zhiwen Chu、Jia Hu、Lu Gao、Zhenlei Song
DOI:10.1021/acs.orglett.5b00437
日期:2015.3.20
functionalized γ-lactones has been developed involving Sakurai exo-cyclization/rearrangement of 3,3-bis(silyl) enolesters with a tethered acetal. While the steric and electronic effects of geminal bis(silane) favor the desired Sakurai pathway, the methoxy species formed in the deprotection step also facilitates both cyclization and rearrangement. The synthetic value of this approach has been demonstrated by efficiently
Synthesis and structure of thienyl Fischer carbene complexes of Pt<sup>II</sup> for application in alkyne hydrosilylation
作者:Zandria Lamprecht、Frederick P. Malan、Simon Lotz、Daniela I. Bezuidenhout
DOI:10.1039/d1nj00791b
日期:——
Transmetallation of group 6 thienylene Fischer carbenecomplexes to PtII precursors yielded new examples of neutral platinum(II) bisethoxycarbene complexes with either 2-thienyl (T) or 5-thieno[2,3-b]thienylene (TT) carbene substituents. The use of analogous aminocarbene group 6 precursors proceeded to give isomeric platinum(II) product mixtures where the resultant bisaminocarbene ligands displayed
将第6组亚噻吩菲舍尔卡宾配合物金属化成Pt II前体产生了具有2-噻吩基(T)或5-噻吩并[2,3- b ]亚噻吩基(TT)卡宾取代基的中性铂(II)双乙氧基卡宾配合物的新实例。使用类似的氨基卡宾第6组前驱体可制得同分异构的铂(II)产品混合物,由于空间需求的TT取代基导致围绕Pt-氨基卡宾键的旋转受到限制,所得的双氨基卡宾配体显示出不同的取向。定义明确的Pt II在使用苯乙炔和三乙基硅烷底物的基准氢化硅烷化反应中,将乙氧基卡宾配合物筛选为催化剂前体。观察到对β- E异构体(E)-三乙基(苯乙烯基)硅烷的明显选择性,并且证明(预)催化剂可循环利用,在无溶剂反应中具有活性,并显示出高炔烃官能团耐受性。