Sequential iodine-mediated diallylsilane rearrangement/asymmetric dihydroxylation: Synthesis and reactions of enantioenriched oxasilacycles
作者:Christopher R. Myers、Paul Spaltenstein、Lauren K. Baker、Cody L. Schwans、Timothy B. Clark、Gregory W. O'Neil
DOI:10.1016/j.tetlet.2021.153392
日期:2021.10
Products from an iodine-mediated diallylsilane rearrangement were taken into an asymmetricdihydroxylation (AD) reaction resulting in the formation of diastereomeric 6-membered oxasilacycles. Removal of the epimeric stereocenter among this mixture of diastereomers by elimination of iodine produced a single enantioenriched cyclic allyl silyl ether. The resulting allyl silane was then successfully engaged
Scope and Limitations of the Scandium-Catalyzed Enantioselective Addition of Chiral Allylboronates to Aldehydes
作者:Dennis G. Hall、Michel Gravel、Hugo Lachance、Xiaosong Lu
DOI:10.1055/s-2004-822359
日期:——
Scandium triflate catalyzes the addition of camphor-derived allyl-, methallyl-, and crotylboronates to aldehydes to provide homoallylic alcohols with excellent diastereo- and enantioselectivity. Aromatic, aliphatic, and propargylic aldehydes can be used successfully in this system. Additional advantages of the camphor-diol allylboronates are their ease of synthesis, their availability in both enantiomeric forms, and their stability towards silica gel chromatography. The usefulness of this methodology is further demonstrated by the gram-scale synthesis of various homoallylic alcohols of high enantiomeric excess and by the concise synthesis of the pheromone (4S)-2-methyloctan-4-ol.
Scandium-Catalyzed Allylboration of Aldehydes as a Practical Method for Highly Diastereo- and Enantioselective Construction of Homoallylic Alcohols
作者:Hugo Lachance、Xiaosong Lu、Michel Gravel、Dennis G. Hall
DOI:10.1021/ja036807j
日期:2003.8.1
A general approach for the allylation of aldehydes using stable, air-tolerant camphor-based chiralallylboronates under Sc(OTf)3 catalysis is described. This practical methodology provides both syn and anti propionate units and other homoallylic alcohols with very high levels of diastereo- and enantioselectivity for several substrates, including functionalized aliphatic aldehydes useful toward the
作者:Thomas R. Hoye、Michael E. Danielson、Aaron E. May、Hongyu Zhao
DOI:10.1021/jo101598y
日期:2010.11.5
has been achieved. The core macrocycle was made via a dual macrolactonization/pyran hemiketal formation reaction, developed to circumvent issues related to the reversible nature of acylketene formation from β-keto lactone substrates. Initial approaches to the core of the natural product that revolved around ring-closingmetathesis (RCM) and relay ring-closingmetathesis (RRCM) reactions are also described
(-)-callipeltoside A ( 1 )的全合成已经实现。核心大环是通过双重大环内酯化/吡喃半缩酮形成反应制成的,开发该反应是为了避免与 β-酮内酯底物形成酰基烯酮的可逆性质相关的问题。还描述了围绕闭环复分解 (RCM) 和中继闭环复分解 (RRCM) 反应的天然产物核心的初步方法。
Synthesis of the Spirocyclic Framework of Sesterterpenoid Natural Products
作者:Jonathan G. Hubert、Daniel. P. Furkert、Margaret A. Brimble
DOI:10.1021/jo502897u
日期:2015.3.6
A convergent synthetic route to the sesterterpenoid framework of the bioactive phorbaketal and alotaketal natural product families has been established. The synthetic approach hinges on a Hosomi–Sakurai coupling of complex acetal and allylsilane coupling partners, followed by DDQ-promoted oxidative cyclization of highly unsaturated advanced intermediates. This robust synthetic approach enables further