Synthesis and Diels–Alder reactions of novel styrylcyclohexenol dienes: a general pathway for the synthesis of tricyclic lactone and octahydronaphthalene systems

Abstract

A series of novel (E)-5,5-dimethyl-3-styrylcyclohex-2-en-1-ol dienes were synthesized by reduction of the respective ketones and their Diels-Alder reactivity explored with Nphenylmaleimide and methyl acrylate. Consequently, two groups of novel products were synthesized in high yields. In reactions with N-phenylmaleimide, the initially formed cycloadducts undergo an additional in situ lactonization to give tricyclic lactone systems, due to spontaneous attack of the allylic hydroxyl on the neighboring carbonyl group of the dienophile residue. All reactions proceeded stereoselectively to give solely the endo products.

A Tandem Aldol Condensation/Diels‐Alder Sequence of Reactions for One‐Pot Synthesis of a New Series of Polysubstituted‐Decalines

“…The endo configuration of the products was concluded from the coupling constants of the CH−Ar and CH−CN single protons with their adjacent CH 2 groups. Such assignment for the cycloaddition reactions of styrylcyclohexyl dienes with other dienophiles is reported before in the literature [25–28] . To further support the assignment, we performed molecular mechanics calculations to verify the endo configuration.…”

“…assignment for the cycloaddition reactions of styrylcyclohexyl dienes with other dienophiles is reported before in the literature. [25][26][27][28] To further support the assignment, we performed molecular mechanics calculations to verify the endo configuration. The outcome of engaging MM2 calculations using ChemSoft's ChemOffice Pro (version 20) clearly show that the endo configuration (Figure 3, top) is more stable than the exo counterpart (Figure 3, middle).…”

“…In the framework of our investigations on the synthesis of new series of conjugated dienes and evaluation of their DA reactivities, [26][27][28] we now would like to report a process for the synthesis of a new series of multisubstituted-decaline derivatives via a one-pot aldol condensation/DA/rearrangement sequence approach, where single endo products are formed in high yields, as exemplified in Scheme 1 for the reaction of enone 1 with 2-chlorobenzaldehyde 2 a and acrylonitrile 3. In the course of the process, the intermediate diene 4 a', which is formed in situ, reacts with the dienophile in the same pot to give the sole adduct 4 a in high yield.…”

One-pot synthesis of benzofurans via heteroannulation of benzoquinones

“…In the framework of our studies on the synthesis of various heterocyclic systems [29][30][31], and in continuation of our program on the use of cyclohexenone derivatives 1a-c in the synthesis [32][33][34], we decided to take advantage of the reactivity of cyclohexenone derivatives for possible coupling with benzoquinone (BQ), as shown in Scheme 1 for the heteroannulation of 1a with BQ. This work resulted in the one-pot synthesis of benzofuran and furanylidenebenzofuran systems 2-4 in PhMe/AcOH (4:1) medium.…”