Gold-Catalyzed Cycloisomerization of 1,6-Diyne Carbonates and Esters to 2,4a-Dihydro-1H-fluorenes
摘要:
A synthetic method to prepare 2,4a-dihydro-1H-fluorenes efficiently from gold(I)-catalyzed 1,2-acyloxy migration/cyclopropenation/Nazarov cyclization of 1,6-diyne carbonates and esters is described. The suggested reaction pathway provides rare examples of [2,3]-sigmatropic rearrangement in this class of compounds as well as the involvement of an in situ formed cyclopropene intermediate in gold catalysis. Experimental and ONIOM(QM:QM') [our own n-layered integrated molecular orbital and molecular mechanics(quantum mechanics quantum mechanics')] computational studies based on the proposed Au carbenoid species provide insight into this unique selectivity.
Gold-Catalyzed Cycloisomerization of 1,6-Diyne Carbonates and Esters to 2,4a-Dihydro-1H-fluorenes
摘要:
A synthetic method to prepare 2,4a-dihydro-1H-fluorenes efficiently from gold(I)-catalyzed 1,2-acyloxy migration/cyclopropenation/Nazarov cyclization of 1,6-diyne carbonates and esters is described. The suggested reaction pathway provides rare examples of [2,3]-sigmatropic rearrangement in this class of compounds as well as the involvement of an in situ formed cyclopropene intermediate in gold catalysis. Experimental and ONIOM(QM:QM') [our own n-layered integrated molecular orbital and molecular mechanics(quantum mechanics quantum mechanics')] computational studies based on the proposed Au carbenoid species provide insight into this unique selectivity.
Gold-Catalyzed [2+2+1] Cycloaddition of 1,6-Diyne Carbonates and Esters with Aldehydes to 4-(Cyclohexa-1,3-dienyl)-1,3-dioxolanes
作者:Weidong Rao、Philip Wai Hong Chan
DOI:10.1002/chem.201303685
日期:2014.1.13
gold(I)‐catalyzed [2+2+1] cycloaddition of 1,6‐diyne carbonates and esters with aldehydes is described. The cascade process involves 1,2‐acyloxy migration followed by cyclopropenation and cycloreversion. This leads to an unprecedented [2+2+1] cycloaddition of the resulting alkenylgold carbenoid species, examples of which are extremely rare, with two aldehyde molecules at catalyst loadings as low as 1 mol %. The