3-Methylcyclohex-2-enone derivatives as initiators of cyclisation. Part 1. Introduction and synthesis of 2-substituted 3-methylcyclohex-2-enones

Regioselective Silver‐Mediated Kondakov–Darzens Olefin Acylation

“…Our silver-mediated acylation of 6 with 3,3-dimethylacryoyl chloride, followed by application of rigorous heating conditions www.chemeurj.org resulted in construction of Oppolzers intermediate 11 [33] in good yield. Oppolzer has converted 11 to modhephene through a stereospecific ene cyclization to Dreidings propellane intermediate (12). [34] In conclusion, we report the intramolecular and intermolecular Kondakov-Darzens reactions in which mild activation of the intermediate acyl halide is achieved using silver triflate.…”

“…[10] The ability to utilize such a transformation for the synthesis of a',a'-disubstituted enones provides a means to circumvent the challenges associated with the direct arylation [11] or alkylation of cyclic enones. [12] Having identified suitable conditions under which to perform this cyclization, we selected the terpene (AE)-cuparene as a viable natural product target. Commercial available tolylpropionic acid (2 a) provides a convenient starting point for a formal synthesis (Scheme 3).…”

Synthesis and Characterization of In-Plane and Out-of-Plane Enone−Lewis Acid Complexes: Implications for Diels−Alder Reactions1

“…We were unable to achieve satisfactory results in the deprotonation and alkylation of 3a , even using n-BuLi/HMPA/THF, or n-BuLi/t-BuOK at temperatures from −78 °C to ambient. As a consequence, we took advantage of the methodology of Sutherland and co-workers, who had experienced difficulties in analogous metalations. Alkylation of 5,6,7,8-tetrahydro-2-naphthol with N , N -diethyl-2-chloroethylamine gave ether 2b (97% yield) which was then reduced to the dienol ether 3b in 95% yield.…”

3-Methylcyclohex-2-enone derivatives as initiators of cyclisation. Part 4. Some bicyclisations

“…Reaction of the epoxides (4) and (5) with BC13-CH2C12 was disappointing. The tetracycle (10) [vmX 3 590 and 1 710 cm-'; 4%) and the chlorohydrin (1 7) (17%). The properties of (1 5 ) and the cyclisation product from the epoxide of 3-methyl-2-pent-3-enylcyclohex-2-enone ' make it clear that they have similar structures and although these have not been rigorously established it is evident that either an elimination-addition or hydride migration has occurred in the initially formed cation (22).…”