A sequential Claisen/ring-closing metathesis approach to the synthesis of spirocyclic cyclopentanes and cyclohexanes
摘要:
A new method for the formation of spirocycles is described using a sequential Ireland-Claisen/Metathesis strategy to construct spirocyclic systems. Optimization of the Ireland-Claisen conditions provides the key metathesis substrates. The metathesis reactions were highly regioselective by virtue of steric hindrance in the substrate olefins. (C) 2003 Elsevier Ltd. All rights reserved.
Sequential 1,4‐/1,2‐Addition of Lithium(trimethylsilyl)diazomethane onto Cyclic Enones to Induce C−C Fragmentation and N−Li Insertion
作者:Matthew J. O'Connor、Chunrui Sun、Xinyu Guan、Venkata R. Sabbasani、Daesung Lee
DOI:10.1002/anie.201510152
日期:2016.2.5
α,β‐Unsaturated ketones generally undergo addition reactions with nucleophiles with a preference for either 1,2‐ or 1,4‐addition, but rarely both. However, the right combination of reagents allows for consecutive 1,4‐ and 1,2‐additions to occur: Cyclic α,β‐unsaturated ketones undergo double additions with lithium(trimethylsilyl)diazomethane, effectively generating various molecular frameworks with