Pd-Catalyzed C(sp<sup>3</sup>)–C(sp<sup>2</sup>) cross-coupling of Y(CH<sub>2</sub>SiMe<sub>3</sub>)<sub>3</sub>(THF)<sub>2</sub> with vinyl bromides and triflates
作者:Guilong Cai、Zhibing Zhou、Wenchao Wu、Bo Yao、Shaowen Zhang、Xiaofang Li
DOI:10.1039/c6ob01765g
日期:——
with vinyl bromides and triflates has been developed for efficient synthesis of various allyltrimethylsilanes. The cross-coupling reaction was conducted at room temperature with low catalyst loading of either Pd(PPh3)4 or Pd(PPh3)2Cl2, and exhibited high efficiency and a broad substrate scope. In combination with the cross-coupling by the Lewis-acid catalyzed Hosomi–Sakurai reaction, a novel three-component
The application of cyclic and acyclic enol ethers as electrophiles in cross coupling reactions offers new possibilities for the preparation of functional compounds.
环状和非环状烯醇醚作为亲电试剂在交叉偶联反应中的应用为功能化合物的制备提供了新的可能性。
The γ-silicon effect. III.1 The Yukawa-Tsuno treatment in the solvolysis of 2-aryl-3-(trimethylsilyl)propyl tosylates
Solvolysis of 2-aryl-3-(trimethylsilyl)propyl tosylate revealed the competitive assistances of the β-aryl and β-(trimethylsilyl)methyl groups. It is found out that the enhanced reactivity by the percaudal interaction of trimethylsilylmethyl group is comparable with that by π-participation of β-phenyl group, and is extraordinarily larger than that by σ-participation of the alkyl group.
Stereoselective Entry into α,α’‐C‐Oxepane Scaffolds through a Chalcogen Bonding Catalyzed Strain‐Release C‐Septanosylation Strategy
作者:Wenpeng Ma、Annika Schmidt、Carsten Strohmann、Charles C. J. Loh
DOI:10.1002/anie.202405706
日期:2024.7.15
The utility of unconventional noncovalent interactions (NCIs) such as chalcogen bonding has lately emerged as a robust platform to access synthetically difficult glycosides stereoselectively. Herein, we disclose the versatility of a phosphonochalcogenide (PCH) catalyst to facilitate access into the challenging, but biologically interesting 7‐membered ring α,α’‐C‐disubstituted oxepane core through an α‐selective strain‐release C‐glycosylation. Methodically, this strategy represents a switch from more common but entropically less desired macrocyclizations to a thermodynamically favored ring‐expansion approach. In light of the general lack of stereoselective methods to access C‐septanosides, a remarkable palette of silyl‐based nucleophiles can be reliably employed in our method. This include a broad variety of useful synthons, such as easily available silyl‐allyl, silyl‐enol ether, silyl‐ketene acetal, vinylogous silyl‐ketene acetal, silyl‐alkyne and silylazide reagents. Mechanistic investigations suggest that a mechanistic shift towards an intramolecular aglycone transposition involving a pentacoordinate silicon intermediate is likely responsible in steering the stereoselectivity.