Four-Electron Electrocyclic Ring-Opening/Intermolecular [4+2] Cycloadditions of α-Hydroxycyclobutenones: Stereoselective Synthesis of Multiple Substituted δ-Lactams
作者:Peidong Song、Qing Li、Congcong Wang、Wenfa Wu、Xu Mao、Jiajia Wang、Xiangdong Hu
DOI:10.1002/adsc.201501152
日期:2016.4.14
four‐electron electrocyclic ring‐opening/intermolecular [4+2] cycloaddition of α‐hydroxycyclobutenones is reported. The reaction represents the first example for the intermolecular cycloaddition of the extensively studied enol‐ketene intermediate, and provides a new synthetic route to multiply substituted δ‐lactams in high stereoselectivity.
New Syntheses and Ring Expansion Reactions of Cyclobutenimines
作者:Ernst Schaumann、Gerrit Oppermann、Michael Stranberg、Harold W. Moore
DOI:10.1071/ch10318
日期:——
cyclobutenediones and an aza-Wittig method. A new synthetic route to N-alkyl derivatives is also presented. This involves O-alkylation of 3-alkylamino-1,2-cyclobutenediones using Meerwein’s reagent and subsequent deprotonation under non-hydrolytic conditions. Lithium organyls were found to add to the remaining carbonyl group. The resulting tertiary alcohols undergo ring enlargement on heating in xylene to give
Methods for the use of inhibitors of cytosolic phospholipase A2 in the treatment of thrombosis
申请人:Clerin Valerie
公开号:US20080009485A1
公开(公告)日:2008-01-10
This invention provides methods for the use of substituted indole compounds of the general formula:
and pharmaceutically acceptable salt forms thereof. The invention provides methods for the use of the compounds in the treating or preventing thrombosis in a mammal, or preventing progression of symptoms of thrombosis.
Nickel-catalyzed ring-opening of α-hydroxycyclobutenones with a remarkable ligand effect
作者:Songsong Gao、Xiangdong Hu
DOI:10.1039/c7cc03340k
日期:——
A Ni-catalyzed ring-opening of α-hydroxycyclobutenones is reported herein. A remarkable ligand effect was observed during transformations following the ring-opening. The employment of PPh3 leads to the formation of 2-furanones 2 through a migration of an alkoxyl group, and 2-furanones 3 were generated through a migration of hydrogen in the presence of Xantphos, affording a divergent approach to 2-furanones
Synthesis of o-quinodimethanes and benzocyclobutenes from dimethyl squarate
作者:John E. Ezcurra、Harold W. Moore
DOI:10.1016/s0040-4039(00)73703-8
日期:1993.9
Selected 3-alkylidene(and benzylidene)-4-allenylcyclobutenes were shown to undergo an unusual thermal ring expansion to o-quinodimethanes and thus to benzocyclobutenes upon electrocyclic ring closure. The mechanism of this rearrangement is envisaged to involve ring opening of the starting cyclobutenes to the corresponding octa-1,2,4,6,7-pentaenes which lead to the quinodimethanes upon ring closure