Organocatalytic Mukaiyama Mannich Reactions of 2,5-Bis(trimethylsilyloxy)furan

Abstract

The organocatalytic synthesis of densely substituted mono- and bis-γ-lactams involving the Mukaiyama Mannich addition of 2,5-bis­(trimethyl­silyloxy)­furan to imines is described. Use of a ditoluene­sulfonylimide catalyst produces γ-lactams from monoaddition, whereas a more acidic catalyst (triflic acid) produces fused bis-lactams from double addition. Optimized organocatalytic conditions allow for the selective synthesis of either desired core as well as the one-pot, multicomponent assembly of the trisubstituted monolactams from aldehydes, amines, and bis-trimethylsilyloxyfuran. An examination of chiral acids found these organocatalysts to be highly active and diastereoselective in the monoaddition reaction, albeit with no enantioselectivity.

Ring‐to‐Thread Chirality Transfer in [2]Rotaxanes for the Synthesis of Enantioenriched Lactams

“…In order to measure the enantiomeric excess of amino acid 22 e , we decided to prepare its corresponding methyl ester. Remarkably, the reaction of the β‐amino acid 22 e in MeOH and in the presence of acid yielded the methylated cis ‐γ‐lactam 23 e , [55] instead of the expected methyl amino ester, observing the release of dibutylamine in the 1 H NMR spectra of the reaction crude. We assumed that the enantiomeric ratio of 23 e (83 : 17 er) was the same at the parent 22 e (not measured).…”

Synthesis of 3,4-dihydroisoquinolin-1(2H)-one derivatives and their antioomycete activity against the phytopathogen Pythium recalcitrans

“…The routes to synthesize the target compounds I1-I34 and II1-II20 are shown in Scheme 1 and 2, following the reported methods. 23,24 To a dry 25 mL roundbottom ask was added anhydrous sodium sulfate (Na 2 SO 4 ) (15.0 mmol), aromatic aldehyde (5.5 mmol), amine (5.0 mmol), and 10 mL of dry DCM successively. The mixture was stirred at room temperature for 24 h. Upon the reaction being completed using TLC for monitoring, the solid was removed by ltration and the residue was evaporated under reduced pressure.…”

Triflamides and Triflimides: Synthesis and Applications

“…The yield of the latter was 64% (with Tf 2 NH) but while using In(OTf) 3 , the yield increased to 80% [40]. The synthesis of monoand bis-γ-lactams by the Mannich method (the addition of 2,5-bis(trimethylsilyloxy)furan to imines) occurs in good yields in the presence triflimide [41]. The intramolecular hydroacyloxylation of non-activated alkenes proceeds well in hexafluoroisopropanol not only with triflimide, but also in the presence of Ca(NTf 2 ) 2 +nBu 4 NPF 6 [42].…”