A new approach to cyclopentane annulated compounds via 1-(cyclopent-1-enylcarbonyl)vinylphosphonates

Abstract

Fused ring systems, containing two or three five-membered rings, were constructed by utilizing 1 -(cyclopent-1 -enylcarbonyl)vinylphosphonates which function as versatile annulating reagents.

Spirodionic Acid, a Novel Metabolite from Streptomyces sp., Part 2: Total Synthesis through a Twofold Michael Addition as a Selective Spiroannelation Strategy

“…In most reports, dibenzylideneacetone, or derivatives thereof, were treated with symmetrical 1,3‐dicarbonyl compounds, such as cyclohexa‐1,3‐dione or malonic acid derivatives, as twofold Michael donors. Only a few examples that employ either chiral enolates as Michael donors16d,h or nonsymmetrical dialkenyl ketones16c,g,i,j,l are known, but none that combines these two features. The required dialkenyl ketone 11 was readily obtained by oxidation with MnO 2 of the respective alcohol, which in turn was prepared by 1,2‐addition of vinylmagnesium bromide to the aldol condensation product of propionaldehyde.…”

Michael Additions to Activated Vinylphosphonates

“…The described methodology was also applied to the synthesis of enantiomerically pure cyclopropylphosphonate analogues of nucleotides. 15 The usefulness of vinylphosphonates in the development of a convenient synthetic route to cyclopentanoid frameworks was demonstrated by Minami et al 16,17 who reported the synthesis of tricyclo[6.3.0.0 3,7 ]undecenones 34a-c, which are terpenoids with potential antibacterial and anticancer activity. The starting b-keto vinylphosphonates 29a-c were prepared by the two methods presented in Scheme 7.…”

“…The same authors 16 used diethyl [3-(cyclopent-1-en-1-yl)-3-oxoprop-1-en-2-yl]phosphonate (29d) as the Michael acceptor in the synthesis of diethyl 6-methylidene-7oxooctahydro-4H-indene-4,4-dicarboxylate (37) (Scheme 9). The intramolecular double Michael addition of diethyl malonate sodium salt (35) to 29d gave adduct S e B r H 2 O 2 C H 2 C l 2 6 3 % P h C H O , C 5 H 1 1 N b e n z e n e , r e f l u x 6 0 % P h C H = N T s , N a H T H F , 7 0 ° C 7 5 % m e t h o d A m e t h o d B ( S ) The particularly attractive Michael acceptors, 3-diethoxyphosphoryl-2(5H)-furanones 40, were synthesized for the first time by Minami et al 18 by phenylselenylation of the corresponding 3-diethoxyphosphoryl-2(3H)-dihydrofuranones 38 and subsequent oxidative elimination of the phe-nylselenyl residue (Scheme 10).…”

Regioselective Proton Abstraction and 1,3-Migration of a Phosphorus Group in 1,3-Dienes by Iron Coordination: A New Method for the Synthesis of α-Phosphono-α,β-unsaturated Ketones

“…Vinylphosphonates containing various functional groups have been widely studied due to their synthetic usefulness . We previously reported that vinylphosphonates having an electron-withdrawing group at the α-position underwent Lewis acid-catalyzed cyclizations, for example, intramolecular ene reactions, [2 + 2] cycloadditions, and Nazarov cyclizations . Our interest in vinylphosphonate chemistry led us to explore the synthesis of cyclic vinylphosphonates bearing an electron-withdrawing group, that is, α-phosphono-α,β-unsaturated cyclic ketones.…”