N-Heterocyclic Carbene-Catalyzed Ireland–Coates Claisen Rearrangement: Synthesis of Functionalized β-Lactones
摘要:
The N-heterocyclic carbene (NHC)-catalyzed Claisen rearrangement of hybrid Ireland-Coates structures has been achieved, allowing the stereoselective synthesis of highly functionalized beta-lactones. The reaction proceeds with high diastereoselectivity (>20:1) and affords a diverse range of beta-lactone fused cyclopentanes. Mechanistic studies are detailed.
N-Heterocyclic Carbene-Catalyzed Ireland–Coates Claisen Rearrangement: Synthesis of Functionalized β-Lactones
摘要:
The N-heterocyclic carbene (NHC)-catalyzed Claisen rearrangement of hybrid Ireland-Coates structures has been achieved, allowing the stereoselective synthesis of highly functionalized beta-lactones. The reaction proceeds with high diastereoselectivity (>20:1) and affords a diverse range of beta-lactone fused cyclopentanes. Mechanistic studies are detailed.
Synthetic and Quantum Mechanical Studies into the <i>N-</i>Heterocyclic Carbene Catalyzed (4 + 2) Cycloaddition
作者:Sarah J. Ryan、Andreas Stasch、Michael N. Paddon-Row、David W. Lupton
DOI:10.1021/jo202500k
日期:2012.1.20
The N-heterocycliccarbenecatalyzed (4 + 2) cycloaddition between α,β-unsaturated acid fluorides and TMS dienol ethers provides cyclohexene fused β-lactone intermediates stable below −20 °C. These can be intercepted reductively or with organolithium reagents to produce diastereomerically pure cyclohexenes (>20:1 dr) with up to four contiguous stereocenters. The mechanism has been investigated using