Synthesis of some fenchyl-substituted alkenes and enol-ethers containing 3-oxyphenyl substituents by the Barton-Kellogg reaction

Abstract

Usando-se a reação de Barton-Kellogg, foram sintetizados um alceno e dois enóis-éteres fenchyl-substituídos, contendo grupos 3-oxifenila como substituintes. O fenchil-alceno aromático tri-substituído 1a foi preparado com rendimento de 53% a partir de tiofenchona e um diazoanisol. A abordagem inversa, baseada no acoplamento entre diazofenchona e tionoésteres aromáticos, foi utilizada para produzir os enóis-éteres 1b e 1c (rendimentos 95 e 75%, respectivamente). Em todos os casos foi obtida uma mistura dos isômeros E e Z; a atribuição e quantificação destes isômeros foram realizadas pela análise dos dados de espectroscopia de RMN assistida por cálculos teóricos (relação E/Z 1a = 0,72, 1b = 2,2, 1c = 1,8). A reação ocorre com baixa estereosseletividade, levando à formação preferencial dos diastereoisômeros das olefinas e enóis-éteres, nos quais o substituinte aromático está localizado ao lado dos dois grupos metila da porção fenchila.The synthesis of one fenchyl-substituted alkene and two enol-ethers, containing 3-oxyphenyl substituents by the Barton-Kellogg reaction is described. The tri-substituted aromatic fenchylalkene 1a was prepared in 53% yield from thiofenchone and a diazoanisole; whereas enol-ethers 1b and 1c were obtained (95 and 75% yield, respectively) using an inverse approach based on diazofenchone and aromatic thionoesters. A mixture of Z and E isomers was obtained in all cases; isomer attribution and quantification has been carried out by analysis of NMR spectroscopic data assisted by theoretical calculations (E/Z ratio: 1a = 0.72, 1b = 2.2, 1c = 1.8). Reaction proceeds with low stereoselectivity leading to the preferential formation of diastereoisomeric olefins and enol-ethers where the aromatic substituent resides at the side of the two fenchyl methyl groups.

Exploring the Structural Space of Chemiluminescent 1,2-Dioxetanes

“…Matsumoto’s bicyclic dioxetane has been demonstrated to have a triggered emission similar to Schaap’s spiroadamantane dioxetane when appended to a meta -phenol using fluoride as a trigger to deprotect a silane protecting group. Other stabilizing groups include a diisopropyl group (Figure C), which interestingly displays higher quantum yields than the spiroadamantane dioxetanes in some cases, and a dioxetane derived from fenchone, developed by Baader and co-workers (Figure D). , The fenchone derivative can be made from cheap starting materials using an accessible synthetic protocol, and Baader’s fenchyl dioxetane displays similar triggerable chemiluminescence as Schaap’s spiroadamantane dioxetane and Matsumoto’s bicyclic dioxetane.…”

Kinetics and mechanism of the Barton–Kellogg olefination: a computational DFT study using CTST theory and topological approaches

“…The BK reaction is a simple and useful method for the formation of substituted olefins and has been applied in the synthesis of light-driven molecular motors, 14 luminescent steroids for intracellular diagnostics, 15 contorted hexabenzocoronenes, which form a class of organic semiconductors and were used as precursors in the synthesis of hemispheric forms of carbon, 16 olefinated heterotriangulenes, 17 conjugated dithioxo olefins, 18 and other basic organic materials. 19…”

Synthesis of unstable cyclic peroxides for chemiluminescence studies

“…39 Contrarily, there are other highly efficient chemiluminescent reactions involving cyclic peroxides, like the intramolecular decomposition of electron-rich 1,2-dioxetanes and the peroxyoxalate reaction, where a cyclic four-membered ring peroxide is believed to occur as an intermediate. 1,[40][41][42][43][44][45][46][47][48][49][50][51][52][53] In contrast to the convenient preparation of sterically-hindered 1,2-dioxetanes, [54][55][56] the difficult synthesis and purification of 1,2-dioxetanones and related cyclic peroxides still limits the investigation of the relationship between their structure and the chemiexcitation efficiency. 1,26 Only the research groups of W. Adam, G. B. Schuster and N. J. Turro have accomplished the synthesis of 1,2-dioxetanone derivatives; however, no other research group has ever reported the synthesis of any of these derivatives, indicating the extreme difficulties in working with this class of compounds.…”