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Asymmetric Diels-Alder reaction is one step in the biosynthesis of the statin lovastatin. [60] The retro-Diels–Alder reaction is used in the industrial production of cyclopentadiene. Cyclopentadiene is a precursor to various norbornenes, which are common monomers. The Diels–Alder reaction is also employed in the production of vitamin B6.
The aza Diels-Alder reaction may occur either by a concerted or stepwise process. The lowest-energy transition state for the concerted process places the imine lone pair (or coordinated Lewis acid) in an exo position.
The Diels-Alder reaction is perhaps the most important and commonly taught cycloaddition reaction. Formally it is a [4+2] cycloaddition reaction and exists in a huge range of forms, including the inverse electron-demand Diels–Alder reaction, hexadehydro Diels–Alder reaction and the related alkyne trimerisation.
The synchronous 6π-electron Diels-Alder reaction is a [π 4 s + π 2 s]-cycloaddition (i.e. suprafacial with respect to both components), as exemplified by the reaction to the right. The Diels-Alder reaction is suprafacial with respect to both components. Thus as the total number of antarafacial components is 0, which is even, the reaction is ...
Depending on the substrate chosen, the HDDA reaction can be initiated thermally or by the addition of a suitable catalyst, often a transition metal. [1] [2] [4] [5] The prevailing mechanism for the thermally-initiated HDDA reaction is a [4+2] cycloaddition between a conjugated diyne (1,3-dialkyne) and an alkyne (often referred to as a diynophile in analogy to the Diels–Alder dienophile) to ...
Oxazolidinone auxiliaries, popularized by David A. Evans, have been applied to many stereoselective transformations, including aldol reactions, [19] alkylation reactions, [20] and Diels-Alder reactions. [21] [22] The oxazolidinones are substituted at the 4 and 5 positions. Through steric hindrance, the substituents direct the direction of ...
The A ring synthesis (Scheme 3) started with a Diels-Alder reaction of diene 3.1 with the commercially available dienophile 2-chloroacrylonitrile 3.2 to give cyclohexene 3.3 with complete regioselectivity. Hydrolysis of the cyanochloro group and simultaneous cleavage of the acetate group led to hydroxyketone 3.4.
It is prepared by isomerization of vinyl norbornene, which in turn is obtained by the Diels-Alder reaction of butadiene and cyclopentadiene. [1] Ethylidene norbornene can be produced in two steps from cyclopentadiene.