Olefination of α,α′-Divinyl Ketones through Catalytic Meyer−Schuster Rearrangement
作者:Curtis J. Rieder、Karl J. Winberg、F. G. West
DOI:10.1021/jo101497f
日期:2011.1.7
followed by catalytic Meyer−Schuster rearrangement has been developed for the olefination of 1,4-pentadien-3-ones to afford [3]dendralenes. Many of the traditional methods for the Meyer−Schuster rearrangement of alkynyl carbinols are not suitable with these highly unsaturated substrates because of their acid sensitivity. Unexpected reactivity during attempted rearrangement, including Nazarov-type electrocyclizations
Formal Homologous Aldol Reactions: Interrupting the Nazarov Cyclization via Carboalkoxylation of Alkynes
作者:Yen-Ku Wu、F. G. West
DOI:10.1021/ol500914a
日期:2014.5.2
Reactions between 1,4-pentadien-3-ones and aryl acetylenes in the presence of BF3·OEt2 furnish α-phenacyl cyclopentanones via a domino electrocyclization/carboalkoxylation reaction sequence. The overall process underscores a new mode of interruptedNazarov trapping, where two new carbon–carbon bonds are installed with concomitant formation of carbonyl functionality.
作者:Yonghoon Kwon、Robert McDonald、Frederick G. West
DOI:10.1002/anie.201303996
日期:2013.8.12
InternAl delivery: Organoaluminum reagents activate 1,4‐dien‐3‐ones for Nazarov electrocyclization (see scheme), then transfer a substituent to the resulting cyclopentenyl cation with moderate to complete regioselectivity and diastereoselectivity.
α-Hydroxycyclopentanones via one-pot oxidation of the trimethylaluminum-mediated Nazarov reaction with triplet oxygen
作者:Yonghoon Kwon、Owen Scadeng、Robert McDonald、F. G. West
DOI:10.1039/c4cc02330g
日期:——
Trimethylaluminum and molecular oxygen are used in tandem to interrupt the Nazarov cyclization. α-Hydroxycyclopentanones are produced in moderate to good yield as a mixture of epimers. This sequence is the first example of combined nucleophilic/electrophilic trapping of the Nazarov oxyallyl intermediate.
Heteroaromatic Trapping of Tricyclic 2-Oxidocyclopentenyl Cations: A Surprisingly Efficient Example of Intermolecular Interrupted Nazarov Reaction
作者:Frederick G. West、Curtis J. Rieder、Ryan J. Fradette
DOI:10.3987/com-09-s(s)132
日期:——
Bis(cycloalkenyl) ketones 2a and 2f underwent Nazarov cyclization and intermolecular trapping by electrophilic aromatic substitution with furans, thiophenes, pyrroles, indoles and dimethoxybenzene. Only the cis-anti-cis diastereomer was isolated with dicyclopentenyl ketone 2a, whereas a mixture of diastereomers was seen with 2f (albeit with complete regioselectivity). Comparable interrupted Nazarov trapping was not seen with acyclic dienones 2b-e, indicating the possible involvement of conformation effects in the polycyclic intermediates derived from 2a and 2f.