Studies on Azetidine Derivatives. IV. Synthesis and Some Reactions of Azetidin-3-one Derivatives

Abstract

Although quite an extensive investigation has been done on azetidin-2-ones, only a few papers have been reported on azetidin-3-one derivatives. The compounds which fall in this category are 1-acetyl-2,2,4,4-tetramethylazetidin-3-one,3)1-benzoylazetidin-3-one4) and 1-t-butyl-2,2-dimethylazetidin-3-one.5)However no direct oxidation of 1-alkyl-azetidin-3-ols6) to the corresponding azetidin-3-ones has been reported. This prompted us to attempt the oxidation of some 1-substituted-alkylazetidin-3-ols to the corresponding azetidin-3-ones which might be useful as intermediates in our studies exploring new azetidine derivatives.Treatment of 1-diphenylmethylazetidin-3-ol (Ia)7) with pyridine-SO3 in DMSO and triethylamine for 30 min8) gave 1-diphenylmethylazetidin-3-one (IIa) in good yield.The strucChart 1 1) A part of this paper was presented at the 3rd International

Strain-Driven Direct Cross-Aldol and -Ketol Reactions of Four-Membered Heterocyclic Ketones

“…Thus, the strained 1a – d ketones invariably act as an electrophile in these reactions of nonequivalent enolizable ketones. As a second issue, these ketones 1a – d seem to have diminished reactivity as a nucleophile in the aldol reaction compared to acetone, as the self-dimerization ketol-product of 1a – d was not observed.…”

Schreiner's Thiourea Promoted [2+2] Cycloaddition of Captodative Azetidinones and Nitroolefins

“…To deal with the first question, the synthesis of captodative olefin 2a was attempted following a straightforward three‐step aldol condensation protocol developed by Masuda . The synthesis began with the direct cross‐aldol reaction of azetidinone 1 with benzaldehyde without any added catalyst.…”

Azacycloalkanes from epoxides and aziridines

“…N-Substituted azetidin-3-ones open a synthetic route to a new group of spiroannulene oxiranes 240 (R = CO 2 Et, Ts, CHPh 2 ) (Scheme 88) [216,217]. …”