Synthetic Entry to the 2-Azatricyclo[4.3.2.0^4,9]undecane Ring System via Tropone

Abstract

A synthesis of the 2-azatricyclo­[4.3.2.04,9]­undecane ring systema hitherto unreported bridged azatricyclic ring systembeginning from tricarbonyl­(tropone)iron and allylamine was accomplished in three steps: (1) aza-Michael addition of allylamine to tricarbonyl­(tropone)­iron; (2) Boc-protection of the resulting secondary amine; and (3) oxidative demetallation leading to a spontaneous intramolecular Diels–Alder reaction. The effect of a variety of parameters on the intramolecular Diels–Alder reaction was investigated, including diene and dienophile substitution patterns and dienophile tether length.

Troponoid Compounds as Therapeutic Agents and as Targets and Templates for Chemical Synthesis

“…68 The modified reactivities associated with the tro-ponoid core of such complexes have been used to good effect, including, as exemplified in Scheme 6, in the assembly of a range of natural products and natural product frameworks. 69 Thus, the parent complex 71 engages in a hetero-Michael addition with allylamine and protection of the 2°a mine of the product as the corresponding toluenesulfonamide gave adduct 72 in 50% overall yield. Decomplexation of the latter compound using ceric ammonium nitrate (CAN) at 0 °C revealed triene 73 that underwent a spontaneous intramolecular Diels-Alder reaction to deliver heterocycle 74 in good yield.…”

Synthetic Approaches to Non-Tropane, Bridged, Azapolycyclic Ring Systems Containing Seven-Membered Carbocycles

“…Tricarbonyl(tropone)iron (197), an air stable complex synthesized in one step from tropone, 60 has previously been used as a starting material in total syntheses. 61 Griffith 62 showed that this complex could serve as a building block for the construction of the novel bridged azatricycle 200 (Scheme 38). The uncomplexed double bond of 197 was shown to participate in an aza-Michael reaction with allylamine.…”

Synthesis of 7-azabicyclo[4.3.1]decane ring systems from tricarbonyl(tropone)iron via intramolecular Heck reactions

“…Thus, comparatively few general methods exist for accessing these scaffolds, even though they are found within a number of biologically active alkaloids. We recently demonstrated that the readily available, bench-stable tricarbonyl(tropone)iron complex [4] (1, Scheme 1) could serve as a precursor to the previously unreported 2-azatricyclo[4.3.2.0 4,9 ]undecane ring system [5] (3, Scheme 1). We sought to demonstrate that this iron complex could serve as a common, versatile building block for additional azapolycyclic skeletons.…”