Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:1 addition reactionbetween hydantoins or thiohydantoins and dialkyl acetylenedicarboxylates in the presence oftriphenylphosphine. These phosphoranes undergo smooth intramolecular Wittig reaction followedby an electrocyclic ring opening to produce dialkyl (E)-2-(2,5-dihydro-5,5-diaryl-2-thioxo-1H-imidazol-4-yl)fum...

Azathioprine (AZA) is a commonly used immunosuppressant for systemic lupus erythematosus (SLE). Myelosuppression is a serious adverse reaction due to AZA and its metabolites. Thiopurine S-methyltransferase (TPMT) is the rate-limiting enzyme. Variations of TPMT enzyme activity may be responsible for myelosuppression. However, a correlation between certain mutant alleles of low TPMT enzyme activi...

Substituted α-alkoxysilanes can be deprotonated by alkyllithium bases and made to undergo Wittig rearrangements to afford the #x0005B;1,4]- and [1,2]-rearranged products in varying ratios. Substitution at the benzylic migrating carbon and/or at the allylic carbon of the allyl moiety impacts the rearrangement reaction, influencing the reactivity as well as the [1,4]-/[1,2]-selectivity. Diastereo...

The sequential 1,4-elimination reaction of (E)-4-alkoxy-2-butenyl benzoates and [1,2]-Wittig rearrangement gave (2Z,4E)-2,4-pentadien-1-ols stereoselectively. Z-Selective formation of intermediary vinyl ethers, whose stereochemistry was well elucidated by the "syn-effect", was achieved by treatment of the 2-butenyl benzoates with KOH in the presence of Pd catalyst. The subsequent [1,2]-Wittg re...

A new and general strategy for highly functional furo[3,4-c]coumarins and related furyl coumarin derivatives has been developed, which is based on an extraordinarily facile intramolecular Wittig reaction, starting from α,β-unsaturated ketones, tributylphosphine, and acyl chlorides. The phosphorus ylides were proposed to be the key intermediates for constructing the crucial furan ring, leading t...

The lithium±metalloid exchange reaction is widely used to prepare synthetically valuable organolithium reagents. The full synthetic potential of one of the most important of these reactions, the Li/I exchange, was not realized (e.g., in the synthesis of alkyllithium reagents) until mechanistic studies showed that it was a well-behaved polar process without a significant radical component.[1a,b,...

The Wittig reaction of perfluorohalobenzaldehydes was systematically studied to synthesize 2,3,5,6-tetrafluoro-4-halostyrene (TFXS) as functional monomers bearing halogen bond donor sites. proceeded efficiently in tetrahydrofuran using 1,1,3,3-tetramethylguanidine the organic base. Correlation analysis quantitatively identified three key factors required obtain TFXS reasonable yields. present a...

The diastereoselective synthesis of cis-2-amino-3-hydroxyindanones was realized by the N-heterocyclic carbene-catalyzed [4 + 1] annulation of phthalaldehyde and imines, which may involve a tandem aza-benzoin reaction and aldol reaction.

A new phenylethyl alkyl amide, (10R)-10-hydroxy-N-phenethyloctadecanamide (1), was isolated from the beetle Ambrostoma quadriimpressum Motschulsky. The structure of the amide was determined by NMR and MS. The absolute configuration of compound 1 was confirmed by an asymmetric total synthesis, which was started from L-glutamic acid. The construction of the aliphatic chain was accomplished by the...

Condensation of 5-nitro, 3-chloro-, and 5-chlorosalicylic acid with formaldehyde afforded dimeric disalicylmethanes which were O-methylated with dimethyl sulfate and oxidized with chromium(VI) oxide to give the diarylketones 10, 11, 12. Wittig reaction with ylides obtained by deprotonation of alkyltriphenylphosphonium salts with sodium bis (trimethylsilyl)amide yielded a series of diarylalkenes...