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• 924-50-5 Methyl 3,3-dimethylacrylate 
• 7032-25-9 (E)-N-(2-pyridylmethylene)aniline 
• 538-51-2 benzylidene phenylamine 
• 40589-40-0 4-bromo-2-methyl-1-buten-3-yne 
• 78-80-8 2-methylbut-1-en-3-yne 
• 76915-33-8 (Z)-((1-methoxy-3-methylbuta-1,3-dien-1-yl)oxy)trimethylsilane 

Relevant academic research and scientific papers

Dualistic Reactivity of Lithium and Zinc Dienolates with Imines: Effects of Counterion, Temperature, and Substituents on α- and γ-Coupling

Lithium and zinc dienolates of 3-butenoic, 3-methyl-2-butenoic, 3-pentenoic, and 4-phenyl-3-butenoic methyl esters are reacted with imines R1C(H)=NR2 .Depending on metal counterion, temperature, and substituents, the C-C coupling occurs either at the 2-position (α-coupling) or at the 4-position (γ-coupling) of the dienolate, giving β-amino esters and α,β-unsaturated esters, respectively.The α-coupling occurs at -78 deg C and is reversible, whereas γ-coupling products are formed upon warming to -20 deg C.The C-C coupled products may undergo irreversible ring closure to β-lactams (from β-amino esters) or 5,6-dihydropyridin-2-ones (from (Z)-α,β-unsaturated esters).Starting from enantiomerically pure imine 3c, high (71-92percent) asymmetric inductions were realized in both β-lactams and 5,6-dihydropyridin-2-ones; γ-coupling of enolate 2a and chiral imine 3d occurred with low diastereoselectivity (15percent).Four factors favor the formation of β-lactams: (i) the use of zinc dienolates, (ii) 4-substitution of the dienolates, (iii) nonaromatic imine N-substituents, and (iv) a low reaction temperature (-78 deg C).The product formation is discussed in terms of six-membered cyclic transition states, involving either zinc enolates (α-coupling) or isomeric allylzinc species (γ-coupling).

Gold-Catalyzed Imination/Mannich Reaction Cascades of 3-En-1-ynamides with Anilines and Aldehydes to Enable 1,5-Nitrogen Functionalizations

Gold-catalyzed imination/Mannich reaction cascades on readily available 3-en-1-ynamides enable the diastereoselective synthesis of 1,5-iminoamino compounds in a one-pot operation. The reactions work well with diversified 3-en-1-ynamides, aldehydes and anilines with good to excellent diastereoselectivities. Our control experiments indicate gold-catalyzed aminations of 3-en-1-ynamides to yield α-imino allylgold intermediates that react subsequently with iminiums to implement the Mannich reactions stereoselectively. The reactions proceed with anti-selectivity for those 3-en-1-ynamides bearing acyclic alkenes whereas syn-selectivity is seen for their cycloalkene-based analogues. An open-transition state can satisfactorily rationalize these observed stereoselectivities based on an antiperiplanar conformation.

REACTIONS OF KETENE SILYL ACETALS WITH IMINE-COMPLEXES OF TITANIUM TETRACHLORIDE. NEW AND CONVENIENT ROUTES TO 5,6-DIHYDRO-2-PYRIDONES AND 5-AMINO-2-ALKENOATES

The reactions of vinylketene silyl acetals (VKSAs) with imine complexes of TiCl4 give the corresponding 5,6-dihydro-2-pyridones and/or 5-amino-2-alkenoates in good to excellent yields.It is suggested that an addition-cyclization mechanism is operative for the formation of 5,6-dihydro-2-pyridones in this formal cyclocondensation reaction.