594-02-5Relevant academic research and scientific papers
Studies on the synthesis of α-iodoaziridines and improved conditions for the synthesis of alkyl-α-iodoaziridines using ClMgCHI2
Boultwood, Tom,Affron, Dominic P.,Bull, James A.
, p. 4949 - 4957 (2015/06/25)
α-Iodoaziridines are unusual motifs and intriguing structures for further functionalisation of the intact aziridine. The preparation of N-protected α-iodoaziridines is achieved through an addition-cyclisation reaction of LiCHI2 with imines. The effects of varying the N-group and using different carbenoids are investigated. Excellent cis-stereochemistry is achieved, except for N-carbamates containing aryl groups. Using the mixed carbenoid LiCHICl, the iodide leaving group is selected for cyclisation affording chloroaziridines only, as a cis/trans mixture. More convenient and higher yielding conditions for the preparation of alkyl N-Ts α-iodoaziridines are developed, using ClMgCHI2. Additionally, the formation of the problematic primary alkyl α-iodoaziridines is achieved.
A dioxane template for highly selective epoxy alcohol cyclizations
Mousseau, James J.,Morten, Christopher J.,Jamison, Timothy F.
supporting information, p. 10004 - 10016 (2013/08/23)
Ladder polyether natural products are a class of natural products denoted by their high functional-group density and large number of well-defined stereocenters. They comprise the toxic component of harmful algal blooms (HABs), having significant negative economic and environmental ramifications. However, their mode of action, namely blocking various cellular ion channels, also denotes their promise as potential anticancer agents. Understanding their potential mode of biosynthesis will not only help with developing ways to limit the damage of HABs, but would also facilitate the synthesis of a range of analogs with interesting biological activity. 1,3-Dioxan-5-ol substrates display remarkable 'enhanced template effects' in water-promoted epoxide cyclization processes en route to the synthesis of these ladder polyether natural products. In many cases, they provide near complete endo-to-exo selectivity in the cyclization of epoxy alcohols, thereby strongly favoring the formation of tetrahydropyran (THP) over tetrahydrofuran (THF) rings. The effects of various Br?nsted and Lewis acidic and basic conditions are explored to demonstrate the superior selectivity of the template over the previously reported THP-based epoxy alcohols. In addition, the consideration of other synthetic routes are also considered with the goal of gaining rapid access to a plethora of potential starting materials applicable towards the synthesis of ladder polyethers. Finally, cascade sequences with polyepoxides are investigated, further demonstrating the versatility of this new reaction template. Reversed selectivity: 1,3-Dioxan-5-ol templated epoxy alcohols undergo a remarkably selective cyclization, which occurs with near complete endo selectivity that is opposite to that predicted by Baldwin's rules. This endo preference in water near pH 7.0 is an order of magnitude larger relative to that of a previously disclosed THP-templated cyclization (see scheme), suggesting that "templates" may be important in the biosynthesis of marine ladder polyethers. Copyright
