Synthesis of perhydroindenes and perhydroisoindoles via one-pot enyne metathesis/Diels-Alder reaction; Remarkable stability of Grubbs catalyst under Lewis acidic conditions

摘要

Perhydroindenes 4a-c and perhydroisoindoles 5a-c were obtained by one-pot enyne metathesis and subsequent Diels-Alder reaction starting from diethyl 4-allyl-4-prop-2-ynyl malonate (1a) or N-allyl-N-prop-2-ynyl p-toluenesulfonamide (1b) and different dienophiles 3a-c in the presence of Grubbs catalyst. The one-pot reactions proceeded with higher yields as compared to the stepwise sequence. Due to the surprising stability of Grubbs catalyst against Lewis acids such as BCl3 and AlCl3, it was also possible to perform one-pot enyne methathesis/Diels-Alder reactions with ethyl acrylate (10) as dienophile giving the perhydroisoindole 11 in good yield. [References: 66]