Cycloaddition Reactions of Deoxyribosylpropynoates

Abstract

GRAPHICAL ABSTRACTAbstract Pure anomers of either α or β 3-(2-deoxyribofuranosyl)propynoates reacted with the tetramethylcyclobutadiene-aluminum trichloride complex to yield the corresponding diastereoisomeric Dewar benzenes. Thermal-or ultraviolet light-initiated rearrangement gave rise to highly substituted C-aryldeoxyribosides as single anomers. The same compounds as well as other substituted deoxyribosides were obtained also by transition metal-mediated cycloaddition reactions.

Cross-metathesis reaction of α- and β-vinyl C-glycosides with alkenes

“…There is a general interest in synthesis of borylated [ 18 ] or carboranylated [ 8 , 19 ] saccharides and derivatives thereof because of their interesting properties. Bearing this in mind, we decided to explore the possibility of attaching the carborane moiety by using a cross-metathesis reaction.…”

“…Thus the ethyne moiety was used in [2 + 2 + 2] cyclotrimerization to yield aryl C -deoxyribosides [ 3 ] and in a Sonogashira reaction for the synthesis of butenolidyl C -deoxyribosides [ 4 ]. Substituted alkynyl C -deoxyribosides [ 5 , 10 – 11 ] were used in other types of cycloaddition reactions providing indolyl C -deoxyribosides [ 6 ], cyclopentenonyl C -deoxyribosides [ 9 ], triazolyl C -deoxyribosides [ 12 – 13 ], carboranyl C -deoxyribosides [ 7 ], and finally also in Diels–Alder reaction with cyclobutadiene derivatives [ 8 ]. Despite of the above mentioned transformations, alkynyl C -deoxyribosides could also be used as a suitable starting material for hitherto rarely studied transformations.…”

Dewar Metallabenzenes from Reactions of Metallacyclobutadienes with Alkynes

“…An effective route to Dewar benzenes is to use [4+2] cycloaddition reactions of cyclobutadienes with alkynes. [17,18] Aminoalkynes are known to undergo [2+2] cycloaddition reactions with electron-deficient alkenes to give aminocyclobutenes. [19] Fischer-type rhenacyclobutadienes are electrophilic and electron-deficient.…”