Domino Metathesis of 2-Azanorbornenones:  A New Strategy for the Enatioselective Synthesis of 1-Azabicyclic Compounds

Abstract

Domino metathesis of N-alkylated derivatives of (1S)-2-azanorborn-5-en-3-one allowed for the enantioselective synthesis of pyrrolizidine, quinolizidine, pyrrolidinoazepine, and pyrrolidinoazocine derivatives in a straightforward process.

Regioselective Domino Metathesis of 7‐Oxanorbornenes and Its Application to the Synthesis of Biologically Active Glutamate Analogues

“…In these runs, desired seven‐membered heterocycles 9b , 9d and 9e were eventually obtained cleanly after a second metathesis reaction, which was performed on the purified bicyclic product in the absence of vinyl acetate (see the Supporting Information). These observations indicated that this metathesis sequence takes place in the order of regioselective ROM, CM and RCM 15. Nitrogen protecting groups were found to have no significant effect on these metathesis reactions (Table 1, run 7 vs. run 8).…”

Ethenolysis: A Green Catalytic Tool to Cleave Carbon–Carbon Double Bonds

“…Ethenolysis of the norbornene substrate 37 catalyzed by first‐generation Ru1 led to the triene 38 in excellent yield without further cyclization, even after prolonged treatment at high temperature (Scheme ) . Treating 38 with second‐generation Ru2 led to complete ring‐closing metathesis to give 39 , showing the drastic influence of the nature of the catalyst in metathesis events . Notably, direct treatment of 37 with Ru2 under ethylene atmosphere led to a poor yield in 39 .…”

“…Some previous examples in which a pendant olefinic group is in the vicinity of a strained cyclic olefin (Scheme , 40 and 41 ) revealed the possibility of cascade ring‐opening/ring‐closing metathesis in competition with the sole ring opening upon ethenolysis . In principle, such cascades, which lead to skeleton rearrangements, are possible in the absence of ethylene.…”

ChemInform Abstract: Ethenolysis: A Green Catalytic Tool to Cleave Carbon—Carbon Double Bonds

“…[51] Treating 38 with second-generation Ru2 led to complete ring-closing metathesis to give 39, showingt he drastic influence of the nature of the catalysti n metathesis events. [51,52] Notably,d irect treatment of 37 with Ru2 under ethylene atmosphere led to apoor yield in 39.…”