Concept explainers
(a)
Interpretation: The product formed by the thermal electrocyclic ring closure of given triene N is to be determined.
Concept introduction: Electrocyclic reactions are pericyclic reactions which takes place by concerted mechanism. These reactions involve ring opening or ring closure in a conjugated polyene.
(b)
Interpretation: The product formed by the photochemical electrocyclic ring closure of given triene N is to be determined.
Concept introduction: Electrocyclic reactions are pericyclic reactions which takes place by concerted mechanism. These reactions involve ring opening or ring closure in a conjugated polyene.
(c)
Interpretation: The given processes are to be labeled as conrotatory or disrotatory.
Concept introduction: Electrocyclic reactions are pericyclic reactions which takes place by concerted mechanism. These reactions involve ring opening or ring closure in a conjugated polyene. In Conratotory process, the orbitals where rearrangement is taking place rotates in clockwise direction and in disrotatory process the atomic orbitals rotates in opposite direction.
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ORGANIC CHEMISTRY >ACCESS CODE<
- What product is formed when each compound undergoes thermal electrocyclic ring opening or ring closure? Label each process as conrotatory or disrotatory, and clearly indicate the stereochemistry around tetrahedral stereogenic centers and double bonds.arrow_forwardWhat cyclic product is formed when each decatetraene undergoes thermal electrocyclic ring closure?arrow_forwarda) What product is formed from the [1,7] sigmatropic rearrangement of a deuterium in the following triene? (b) Does this reaction proceed in a suprafacial or antarafacial manner under thermal conditions? (c) Does this reaction proceed in a suprafacial or antarafacial manner under photochemical conditions?arrow_forward
- The endiandric acids comprise a group of unsaturated carboxylic acids isolated from a tree that grows in the rain forests of eastern Australia. The methyl esters of endiandric acids D and E have been prepared from polyene Y by a series of two successive electrocyclic reactions: thermal ring closure of the conjugated tetraene followed by ring closure of the resultingconjugated triene. (a) Draw the structures (including stereochemistry) of the methyl esters of endiandric acids D and E. (b) The methyl ester of endiandric acid E undergoes an intramolecular [4 + 2] cycloaddition to form the methyl ester of endiandric acid A. Propose a possible structure for endiandric acid A.arrow_forwardThe endiandric acids comprise a group of unsaturated carboxylic acids isolated from a tree that grows in the rainforests of eastern Australia. The methyl esters of endiandric acids D and E have been prepared from polyene Y by a series of two successive electrocyclic reactions: thermal ring closure of the conjugated tetraene followed by ring closure of the resulting conjugated triene. (a) Draw the structures (including stereochemistry) of the methyl esters of endiandric acids D and E. (b) The methyl ester of endiandric acid E undergoes an intramolecular [4 + 2] cycloaddition to form the methyl ester of endiandric acid A. Propose a possible structure for endiandric acid A.arrow_forwardThe spirocyclic pentadiene derivative F shown below is converted stereospecificallyinto compound G on heating. The transformation involves two consecutive pericyclicreactions of the same type, and proceeds via compound H which is not isolated. Identify the type of pericyclic reaction occurring, and determine the structure ofcompound H.arrow_forward