Transannular [4+3] Cycloadditions of Macrocyclic Epoxy Ketones

Abstract

Transannular [4+3] cycloadditions of dienophiles derived from macrocyclic epoxy ketones produce fused ring systems having central cycloheptane subunits. In some cases, the base directly induced cycloisomerization of the epoxy ketones to yield the cycloadducts; in others, the epoxy ketones were transformed into their corresponding enolsilanes before undergoing cycloaddition. Enantiomerically enriched tricyclic arrays were obtained from cycloadditions starting from optically pure epoxy ketones.

Dearomative Intramolecular (4+3) Cycloadditions of Thiophenes

“…[30] Our group has a long-standing interest in the (4+3) cycloadditions of epoxy and aziridinyl enolsilanes with dienes. [31][32][33][34][35][36][37][38] These (4+3) cycloadditions have achieved the dearomatization of arenes and heteroaromatics to afford bridged cycloheptanes. As it is clear that dearomative cycloadditions of thiophene are neither expected nor common, whether this kind of substrate could be within the scope of this reaction was uncertain.…”

“…Our group has a long‐standing interest in the (4+3) cycloadditions of epoxy and aziridinyl enolsilanes with dienes [31–38] . These (4+3) cycloadditions have achieved the dearomatization of arenes and heteroaromatics to afford bridged cycloheptanes.…”

Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones

“…There are several different ways in which TCRs can occur, depending on the nature of the starting materials and the conditions used [5]. Some common types of TCRs include Diels-Alder reactions [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], photocycloadditions [21][22][23][24][25][26][27][28], and other types of multistep cycloadditions [29].…”