N-Heterocyclic Carbene-Catalyzed (4 + 2) Cycloaddition/Decarboxylation of Silyl Dienol Ethers with α,β-Unsaturated Acid Fluorides
摘要:
Herein we report the first all-carbon N-heterocyclic carbene-catalyzed (4 + 2) cycloaddition. The reaction proceeds with alpha,beta-unsaturated acid fluorides and silyl dienol ethers and produces 1,3-cyclohexadienes with complete diastereocontrol (dr > 20:1) while demonstrating a new type of reaction cascade exploiting alpha,beta-unsaturated acyl azoliums.
N-Heterocyclic Carbene-Catalyzed (4 + 2) Cycloaddition/Decarboxylation of Silyl Dienol Ethers with α,β-Unsaturated Acid Fluorides
摘要:
Herein we report the first all-carbon N-heterocyclic carbene-catalyzed (4 + 2) cycloaddition. The reaction proceeds with alpha,beta-unsaturated acid fluorides and silyl dienol ethers and produces 1,3-cyclohexadienes with complete diastereocontrol (dr > 20:1) while demonstrating a new type of reaction cascade exploiting alpha,beta-unsaturated acyl azoliums.
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
N-Heterocyclic Carbene-Catalyzed (4 + 2) Cycloaddition/Decarboxylation of Silyl Dienol Ethers with α,β-Unsaturated Acid Fluorides
作者:Sarah J. Ryan、Lisa Candish、David W. Lupton
DOI:10.1021/ja111067j
日期:2011.4.6
Herein we report the first all-carbon N-heterocyclic carbene-catalyzed (4 + 2) cycloaddition. The reaction proceeds with alpha,beta-unsaturated acid fluorides and silyl dienol ethers and produces 1,3-cyclohexadienes with complete diastereocontrol (dr > 20:1) while demonstrating a new type of reaction cascade exploiting alpha,beta-unsaturated acyl azoliums.