Stereoselective synthesis of trans-hydroazulene derivatives by tandem Michael-intramolecular Wittig reactions of a cyclic phosphonium ylide with alkyl or aryl 1-cyclopentenyl ketones

Synthesis of 2,6-disubstituted tetrahydroazulene derivatives

“…The stereoselective synthesis of trans -hydroazulene derivatives by a tandem Michael/intramolecular Wittig approach was reported previously [5]. Recently, a new synthetic method for the construction of a hydroazulene skeleton by a [5 + 2]cycloaddition reaction was also developed [6].…”

“…Hydroazulene skeletons provide the basic ring systems of natural products, such as guaianolide sesquiterpenes [ 1 – 2 ] and the so-called furanether B series [ 3 – 4 ]. The stereoselective synthesis of trans -hydroazulene derivatives by a tandem Michael/intramolecular Wittig approach was reported previously [ 5 ]. Recently, a new synthetic method for the construction of a hydroazulene skeleton by a [5 + 2]cycloaddition reaction was also developed [ 6 ].…”

Diastereoselective Synthesis of a Hydroazulene Derivative by Tandem Michael-Wittig Reactions

“…Nagao et al the reaction of [1] with t-butyl ester 2(R=t-Bu) was carried out under the same reaction conditions. Consequently, the desired hydroazulene derivative 3 was obtained in 60% yield with similar stereoselectivity.…”

Reaction of a Cyclic Oxosulfonium Ylide with Acetates of the Baylis-Hillman Adducts: Tandem Michael−Intramolecular Corey-Chaykovsky Reactions

“…The reaction of a five-membered cyclic phosphonium ylide with enones, enoates, and α,β-unsaturated thioesters provides cycloheptene or hydroazulene derivatives by tandem Michael−intramolecular Wittig reactions. These tandem reactions proceed via a rigid phosphabicyclic or phosphatricyclic intermediate so that the products form with stereoselectivity.…”