ChemInform Abstract: Reactions of Unsaturated Compounds. Part 131. Reaction of Eneallenylphosphonates (I), (VII), and α,β‐Unsaturated Phosphoryl Ketones (IX) with Chromyl Chloride.

Mo(CO)6-Mediated Intramolecular Pauson−Khand Reaction of Substituted Diethyl 3-Allyloxy-1-Propynylphosphonates

“…Several approaches to monocyclic substituted 2-phosphonocyclopentenones have been reported in the literature. For instance, as byproduct in low yield from ϵ- tert -butyldimethylsilyloxy-α-diazo-β-ketophosphonates via a rhodium(II)-catalyzed C−H insertion reaction, − by ozonolysis/intramolecular aldol condensation of β-keto-ω-alkenylphosphonates requiring a multistep reaction, from diethyl-2(5-methyl)furyl-hydroxymethylphosphonate via diethyl hex-3-en-2,5-dione-1-ylphosphonate followed by reduction and condensation, by conversion of cyclic vinyl sulfones to vinylphosphonates, and by Arbuzov reaction of cyclohexenylbromide (one example) and as mixtures in low yield from enallenic phosphonates and α,β-unsaturated phosphoryl ketones with chromyl chloride. , This being the case, we decided to explore the possible use of 1-alkynylphosphonates in an intramolecular PKR, and in this paper, we describe our results for the general synthesis of the novel diethyl 3-substituted-5-oxo-3,5,6,6a-tetrahydro-1 H -cyclopenta[ c ]furan-4-ylphosphonates 2 from diethyl 3-allyloxy-1-propynylphosphonates 1 . The preparation of 2 has not been previously reported.…”