[2 + 2] Photochemical cycloaddition/ring opening of 6-alkenyl-2,3-dihydro-4-pyridones.
During the course of a study aimed at constructing azaspirocycles from 2,3-dihydro-4-pyridones, an unexpected product was obtained in the SET ring-opening reaction of photocycloadduct 1. Differences in reactivity between homologues 1 and 2 were observed in the presence of SmI(2). Tricyclic ketone 2 afforded azaspiro[5.5]undecane 15 when treated with SmI(2); however, when ketone 1 was submitted to similar reaction conditions a double ring-opening/reduction sequence gave cis-piperidinol 10.
Sahn
James J
JJ
Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA.
Comins
Daniel L
DL
D003500:Cyclization; D015394:Molecular Structure; D010777:Photochemistry; D011728:Pyridones / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D011728:Pyridones