Efficient syntheses are described for the synthetically important 3-methylquinoline-4-carbaldehydes 6a-h from o-nitrobenzaldehydes 1a-h employing a Wittig-olefination-Claisen-rearrangement protocol. The Wittig reaction of o-nitrobenzaldehydes with crotyloxymethylene triphenylphosphorane afforded crotyl vinyl ethers 2a-h, which on heating under reflux in xylene underwent Claisen rearrangement to...

Lewis acid-catalyzed reaction of allyl and benzyl trichloroacetimidates with r-silyl alcohols was found to be a general method for the synthesis of r-alkoxysilanes. Upon exposure to CsF, these r-alkoxysilanes could be made to undergo [2,3]-Wittig rearrangement with an efficiency similar to that realized by the analogous but inherently more toxic r-alkoxystannanes. For over 20 years Wittig rearr...

The combination of small-molecule catalysis and enzyme represents an underexploited area research with huge potential in asymmetric synthetic chemistry due to both compatibility reaction conditions complementary reactivity. Herein, we describe the telescopic synthesis chiral nitro alcohols starting from commercially available benzaldehyde derivatives through one-pot three-step chemoenzymatic ca...

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...

The choice is yours: a highly stereoselective synthesis of α-alkyl-α-hydroxy-β-amino esters is accomplished through a tandem Wittig-rearrangement/Mannich reaction sequence. Transformations of N-benzyl or N-Boc imines proceed with high selectivity for formation of syn-amino alcohol derivatives, whereas N-Boc-2-(phenylsulfonyl)amines generate anti-amino alcohol products. Auxiliary cleavage (trans...

The use of t-BuLi at low temperature selectively leads to α-lithiation of benzyl phenyl ether generating a stable organolithium, which can be efficiently trapped with a variety of selected electrophiles prior to suffering the expected [1,2]-Wittig rearrangement. In the case of (o-alkynyl)phenyl benzyl ethers, the intermediate α-aryloxyorganolithium undergoes an unexpected anti intramolecular ca...