Some Typical Advances in the Synthetic Applications of Allenes

Abstract

In 1989, Kakiuchi et al. reported that under irridation propadiene can undergo [2+2]-cycloaddition with R,β-unsaturated cyclohexenones to afford methylene-cyclobutane-containing bicyclic products 1 (Scheme 1). 6 Shi et al. reported that under the catalysis of DABCO, N-tosylated imines 2 can undergo [2+2]cycloaddition with 2,3-butadienoate or 3,4-pentadien-2-one to afford azetidine derivatives 3. 7 The reaction proceeded via the nucleophilic addition of DABCO to the electron-deficient allene forming 4-and 5-type intermediate, which may undergo 1,2-addition with the imines to afford 6. Intramolecular conjugate Scheme 1

Distannylierung und Silastannylierung in situ generierter Allene

“…[2] Von besonderem Interesse ist die katalytische Dimetallierung der Allene, [3] da die entstehenden Produkte sowohl eine vinylische als auch eine allylische Metallgruppe enthalten. Beide metallorganischen Funktionalitäten lassen sich gezielt und selektiv umsetzen, was die Produkte der katalytischen Dimetallierung von Allenen zu wertvollen, hoch funktionalisierten Bausteinen für die organische Synthese macht.…”

Regio- and stereoselective Diels-Alder reaction of diphenyl 5-methylhexa-1,3,4-trien-3-yl phosphine oxide with N-(4-substituted-phenyl)maleimides and maleic anhydride

“…[7][8][9][10][11] Among the many different dienes and dienophiles employed in Diels-Alder reaction, allenes have played only a minor role. [12][13][14][15] In most cases, they have been used as dienophiles (II) (see Scheme 1) and converted into cycloadducts (III) by reactions with dienes (I). [16][17][18][19][20][21] If the allene bears another conjugated double bond, however, it can be used as the diene component (IV), and the DielsAlder reaction with dienophiles (V) gives cycloadducts with an exocyclic double bond (VI).…”

Microwave-assisted reactions of allenic esters: [3+2] annulations and allenoate-Claisen rearrangement

“…[1][2][3][4] The inherent instability associated to the cumulated double bonds has been widely exploited for synthetic purposes. This structural feature makes addition to allenes very favourable, since it involves a relief in strain.…”