Silver‐Catalyzed Epoxidation of Aldehydes Using Donor‐/ Acceptor‐type Vinyl Diazosuccinimides to Access Spiro‐Pyrrolidinedioneoxiranes

Abstract

A silver(I)-catalyzed method to access spiro-pyrrolidinedioneoxiranes has been developed. Silver hexafluoroantimonate was found to be an efficient catalyst for the epoxidation of aldehydes using donor-/acceptor-substituted vinyl diazosuccinimides as carbenoid precursors. The protocol has been found to be highly regio-and chemoselective, and works well with aromatic aldehydes containing electronwithdrawing and -donating groups to afford spiro-pyrrolidinedioneoxiranes with a broad substrate scope. Dr. Homi

Diazo Glutaconimides: an Unexplored Type of Heterocyclic α‐Diazocarbonyl Compounds Conveniently Evolved into Pyridine‐2,6(1H,3H)‐diones and Oxazolo[5,4‐b]pyridin‐5(4H)‐ones

“…1‐Isopentyl‐4‐mesitylpyridine‐2,6(1 H ,3 H )‐dione (5 n) : yield 254 mg (85 %), orange foam. NMR spectra of the obtained substance correspond to literature data [16] . HRMS (ESI): m / z calcd for C 19 H 25 NO 2 +Na + : 322.1778 [ M +Na] + ; found 322.1772.…”

“…[13] Continuing this line of inquiry, diazo barbituric acids 2 were successfully prepared and involved in the preparation of biologically relevant oxazolo [5,4-d]pyrimidine-5,7-diones via Rh (II)-catalyzed condensation with nitriles. [14] Most recently, we [15] and others [16] introduced (E)-3-arylidene-4-diazopyrrolidine-2,5diones 3 also prepared via direct diazo transfer to readily available 3-arylidene pyrrolidine-2,5-diones. Compounds 3 have been shown to undergo metal carbene-mediated XÀ H insertion reactions [15] and [2 + 1] cycloaddition with aldehydes; [16] their synthetic potential continues being unraveled in our laboratories.…”

“…[14] Most recently, we [15] and others [16] introduced (E)-3-arylidene-4-diazopyrrolidine-2,5diones 3 also prepared via direct diazo transfer to readily available 3-arylidene pyrrolidine-2,5-diones. Compounds 3 have been shown to undergo metal carbene-mediated XÀ H insertion reactions [15] and [2 + 1] cycloaddition with aldehydes; [16] their synthetic potential continues being unraveled in our laboratories. [17] Recently we developed the synthesis of 3arylpent-2-enedioic (β-arylglutaconic) acids [18] and successfully employed them and their anhydrides in various multicomponent transformations.…”

(E)-3-Arylidene-4-diazopyrrolidine-2,5-diones: Preparation and Use in RhII-Catalyzed X–H Insertion Reactions towards Novel, Medicinally Important Michael Acceptors

“…When this work was in progress, a report from Bhat and Laha appeared in the literature which also explored a diazo-transfer approach to compounds 2 and their use in silver-catalyzed [2+1] cycloaddition with aldehydes. 20 This prompts us to disclose our findings in this regard that can, on the one hand, provide some distinct practical convenience at the diazo-transfer stage towards 2 and, on the other hand, firmly validate the use of 2 in transition-metalcatalyzed X-H insertion reactions as the means to prepare novel Michael acceptors 3 for biological investigation.…”

“…This resulted in excellent yields of all diazo compounds 2a-f (Table 1). A notable feature of this protocol is the redundancy of aqueous workup (in contrast to the Bhat procedure 20 ), as in our case the crude reaction mixture was loaded directly onto a silica gel column for chromatographic purification. For Table 1, entry 1, we compared the yield of the diazo product to that obtained in aqueous medium using the recently developed 'sulfonyl-azide-free' (SAFE) diazo transfer.…”