Synthesis of Bridged Polycyclic Ring Systems via Carbene Cascades Terminating in C–H Bond Insertion
作者:Santa Jansone-Popova、Jeremy A. May
DOI:10.1021/ja308305z
日期:2012.10.31
A carbene cascade reaction that constructs functionalized bridged bicyclic systems from alkynyl diazoesters is presented. The cascade proceeds through diazo decomposition, carbene/alkyne metathesis, and C H bond insertion. The diazoesters are easily synthesized from cyclic ketones. Substrate ring size and substitution patterns control the connectivity and diastereomeric preference found in the products.
Transition Metal-Free <i>trans</i>-Selective Alkynylboration of Alkynes
We report the first transition metal-free and trans-selective alkynylboration reaction of alkynes. This unprecedented carboboration reaction is enabled by pseudo-intramolecular activation of alkynylboronates using propargylic alcohols. The carboboration affords 4-alkynyl-1,2-oxaborol-2(5H)-ols, which are not only versatile building blocks but also exhibit strong violet blue fluorescence emission.