911028-87-0Relevant academic research and scientific papers
Synthesis of Isothiocineole and Application in Multigram-Scale Sulfur Ylide Mediated Asymmetric Epoxidation and Aziridination
Fearraigh, Martin P. ó,Matlock, Johnathan V.,Illa, Ona,McGarrigle, Eoghan M.,Aggarwal, Varinder K.
, p. 3337 - 3343 (2018/09/04)
The synthesis of the chiral sulfide isothiocineole from limonene and elemental sulfur on multi-gram scale and its alkylation to make >50 g of the corresponding benzylsulfonium salt are described. The application of this salt to the sulfur ylide-mediated asymmetric epoxidation of aldehydes and the asymmetric aziridination of imines on a >5 g scale is demonstrated.
Practical and highly selective sulfur ylide-mediated asymmetric epoxidations and aziridinations using a cheap and readily available chiral sulfide: Extensive studies to map out scope, limitations, and rationalization of diastereo- and enantioselectivities
Illa, Ona,Namutebi, Mariam,Saha, Chandreyee,Ostovar, Mehrnoosh,Chen, C. Chun,Haddow, Mairi F.,Nocquet-Thibault, Sophie,Lusi, Matteo,McGarrigle, Eoghan M.,Aggarwal, Varinder K.
supporting information, p. 11951 - 11966 (2013/09/02)
The chiral sulfide, isothiocineole, has been synthesized in one step from elemental sulfur, γ-terpinene, and limonene in 61% yield. A mechanism involving radical intermediates for this reaction is proposed based on experimental evidence. The application of isothiocineole to the asymmetric epoxidation of aldehydes and the aziridination of imines is described. Excellent enantioselectivities and diastereoselectivities have been obtained over a wide range of aromatic, aliphatic, and α,β-unsaturated aldehydes using simple protocols. In aziridinations, excellent enantioselectivities and good diastereoselectivities were obtained for a wide range of imines. Mechanistic models have been put forward to rationalize the high selectivities observed, which should enable the sulfide to be used with confidence in synthesis. In epoxidations, the degree of reversibility in betaine formation dominates both the diastereoselectivity and the enantioselectivity. Appropriate tuning of reaction conditions based on understanding the reaction mechanism enables high selectivities to be obtained in most cases. In aziridinations, betaine formation is nonreversible with semistabilized ylides and diastereoselectivities are determined in the betaine forming step and are more variable as a result.
Palladium-mediated annulation of vinyl aziridines with michael acceptors: Stereocontrolled synthesis of substituted pyrrolidines and its application in a formal synthesis of (-)-α-kainic acid
Lowe, Martin A.,Ostovar, Mehrnoosh,Ferrini, Serena,Chen, C. Chun,Lawrence, Paul G.,Fontana, Francesco,Calabrese, Andrew A.,Aggarwal, Varinder K.
, p. 6370 - 6374 (2011/09/12)
Just add salt: Vinyl aziridines have been treated with methyl vinyl ketone or ethyl thioacrylate in the presence of Pd0 to give pyrrolidines with moderate to good diastereoselectivity. The presence of nBu4NCl was critical to successf
Practical and highly selective sulfur ylide mediated asymmetric epoxidations and aziridinations using an inexpensive, readily available chiral sulfide. Applications to the synthesis of quinine and quinidine
Illa, Ona,Arshad, Muhammad,Ros, Abel,McGarrigle, Eoghan M.,Aggarwal, Varinder K.
supporting information; experimental part, p. 1828 - 1830 (2010/04/25)
(Chemical Presented) Heating one of the most abundant naturally occurring inorganic chemicals (elemental sulfur) with one of the most readily available homochiral molecules (limonene) gives a one-step synthesis of a chiral sulfide which exhibits outstanding selectivities in sulfur ylide mediated asymmetric epoxidations and aziridinations. In particular reactions of benzyl and allylic sulfonium salts with both aromatic and aliphatic aldehydes gave epoxides with perfect enantioselectivities and the highest diastereoselectivities reported to date. In addition reactions with imines gave aziridines again with the highest enantioselectivities and diastereoselectivities reported to date. The reactions are scaleable, and the sulfide can be reisolated in high yield. The epoxidation has been used as the key step in a convergent and stereoselective synthesis of each of the diastereoisomers of the cinchona alkaloids, quinine and quinidine. Copyright
