13159-14-3

Upstream product

• 13159-19-8 diethyl (E)-2-(5-phenylpent-4-enyl)malonate 
• 14112-98-2 7-oxooctanoic acid 
• 100-52-7 benzaldehyde 
• 28525-69-1 (4E)-5-phenyl-4-pentenoic acid 
• 13161-18-7 2-[hydroxy(phenyl)methyl]cyclohexanone 

Downstream Products

• 124553-47-5 3-amino-2-(6-phenylhex-5-enyl)quinazolin-4(3H)-one 
• 124553-48-6 C₂₀H₁₉N₃O 
• 148989-82-6 7-(2-hydroxy-3,4,6-trimethylphenyl)-7-phenylheptanoic acid 
• 121099-59-0 7-(4-fluorophenyl)-7-(3-formyl-6-hydroxy-2,4,5-trimethylphenyl)heptanoic acid 
• 393569-33-0 (S)-5-(4-Benzyloxy-phenyl)-4-(7-phenyl-heptanoylamino)-pentanoic acid methyl ester 

Relevant academic research and scientific papers

Cyclization of 5-hexenyl radicals from nitroxyl radical additions to 4-pentenylketenes and from the acyloin reaction

Photochemical Wolff rearrangements were used to form 5-substituted-4-pentenylketenes 1a-1d (RCH=CHCH2X-CH 2CH=C=O: 1a R = H, X = CH2; 1b R = Ph, X = CH 2; 1c R = c-Pr, X = CH2; 1d R = H, X = O), which were observed by IR at 2121, 2120, 2119, and 2126 cm-1, respectively, as relatively long-lived species at room temperature in hydrocarbon solvents. These reacted with the nitroxyl radical tetramethylpiperidinyloxyl (TEMPO, TO·) forming carboxy-substituted 5-hexenyl radicals 3, which were trapped by a second nitroxyl radical forming 1,2 diaddition products 4a-4d. On thermolysis, 4a-4d underwent reversible reformation of the radicals 3, which underwent cyclization forming cyclopentanecarboxylic acid derivatives 6 or 11 as the major products. However, in the case of 1b, the cyclopentane derivative was formed reversibly and on prolonged reaction times the only product isolated was PhCH=CH-(CH2)4CO2H (8b) from hydrogen transfer to Cβ and cleavage of the TEMPO group. Cyclopropylcarbinyl radical ring opening in the cyclized radical 5c from 1c led to the 2-(4-N-tetramethylpiperidinyloxybut-1-enyl)cyclopentane derivative 11 as the major product. In a test for 5-hexenyl radical ring closure in the radical anion intermediate of the acyloin condensation, the ester CH 2=CH(CH2)3CO2Et (12a) gave the acyloin 13a (76%) as the only observed product, while PhCH=CH(CH 2)3CO2CH3 (12b) with Na in toluene gave 21% of the acyloin product 13b and 42% of 2-benzylcyclopentanol (15) from cyclization of the intermediate radical anion.

The aldol-Grob reaction: Regioselective synthesis of (E)-alkenes from aldehydes and ketones with ytterbium triflate catalysis

A simple, good yielding and solvent-free aldol-Grob reaction sequence, catalysed by Yb(OTf)3 hydrate, affording (E)-alkenes regioselectively from aldehydes and ketones is described. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.