A general catalytic enantioselective method that can produce five-, six-, and seven-membered N-heterocycles possessing various ketone moieties starting from stable and easily available cyclic hemiaminals and ketones was developed. The method involves three successive steps in one pot (aldol addition, dehydration, and enantioselective intramolecular aza-Michael reaction), all of which are promoted by
functionalized dihydro-[1,3]oxazino[4,3-a] isoindole and tetrahydroisoquinoline skeletons has been developed through the addition-cyclization process of ynamides 8 with N-acyliminium ions generated from N,O-acetals 6,7. The reactions were conducted under the catalysis of Cu(OTf)2, and a number of functionalized dihydro-[1,3]oxazino[4,3-a] isoindoles 9a-9y and tetrahydroisoquinolines 10a-10g, 11a-11p
A practical approach to α-aminophosphonates has been developed through an In(OTf)3-catalyzed N-α phosphonylation of N,O-acetals with triethylphosphite 7. Indoline and isoindoline N,O-acetals 6a–6j and 9a–9j and chain N,O-acetals 11a–11p were subjected to a Lewis acid catalyzed N-α phosphonylation process. As a result, the desired α-aminophosphonates 8a–8j, 10a–10j and 12a–12p were obtained in moderate