Synthesis of polysubstituted dioxoles from the cycloaddition of diazo dicarbonyl compounds to aldehydes and ketones under copper(II) catalysis

Efficient synthesis of β-substituted α-chloro enones by rhodium(ii)-catalyzed reactions of cyclic diazodicarbonyl compounds with acid chlorides

“…Treatment of 2-diazocyclohexane-1,3-dione 1 with AcCl at room temperature for 3 h gave the 3-acetoxy-2-chlorocyclohex-2-enone 6 in 81% yield, without a trace of expected 1,3-dioxole 7 (Scheme 2). 9 Support for the structural assignment comes from spectroscopic analysis. The enone 6 is identified by the IR carbonyl absorptions of the enone at 1693 cm 21 and the vinyl ester at 1777 cm 21 , and the 1 H NMR peak of the methyl group of the vinyl acetate as a singlet at d 2.26.…”

“…Importantly, our result is in clear contrast to that of Alonso who reported that the copper(II)-catalyzed reaction of acyclic methyl 2-diazo-3-oxobutyrate with carbonyl compounds such as aldehydes or ketones afforded 1,3-dioxole adducts in moderate yields. 9 In order to extend the utility of this methodology, reactions of more complex diazodicarbonyl compounds 3-5 with acid chlorides were examined. In these cases, only a single product was also detected.…”

Formal gas‐phase polar [4 + 1+] cycloaddition of ionized methylene to α‐dicarbonyl compounds: synthesis of 2‐unsubstituted 1,3‐dioxoles

“…Since + CH 2 OCH 2 · is accessible in the condensed phase,19 such reactions may also be attempted for the solvated ion. Therefore, this formal cycloaddition of the simplest ionized carbene may be added to the set of the few methods available for the synthesis of 1,3‐dioxoles 20–22. It also shares some analogy with the solution cycloaddition of dicarbonyl carbenes to aldehydes and ketones, which was found to form polysubstituted 1,3‐dioxoles 20…”

Spirocyclic Amide Acetal Synthesis by [CpRu]‐Catalyzed Condensations of α‐Diazo‐β‐Ketoesters with γ‐Lactams

“…These reactive intermediates condense to form epoxides ( A , path a ), act as 1,3‐dipoles in intra‐ and intermolecular cycloadditions ( A , path b ) or form enol ethers ( A , path c ) [26–30] . Using α‐diazo‐β‐ketoesters as reagents, carbonyl ylides evolve toward the formation of dioxolene adducts instead that are formed by intramolecular condensation ( A , path d ) [31–38] . While such a process occurs quite readily with aldehydes and ketones, but also with esters (lactones) and cyclic carbonates, [32] examples of dioxolene formation with amide functional groups are rare.…”