5- valerolactame

Six years later, the same authors reported an improved version of their earlier synthesis of ellipticine (228) (527) (Scheme 5.197) by using the l-(p-methoxybenzyl)-5,6-dihydropyridone (1197) as 3,4-pyridyne surrogate (702,703). Thus, the dimethyl-furoindole 544 was treated with the unsaturated lactam 1197 (prepared from 5-valerolactam in three steps) in the presence of trimethylsilyl triflate (TMSOTf) to afford the carbazole 1199 as a single product in 40% yield. The low yield is presumably a consequence of decomposition of the intermediate adduct 1198 during... 

Besides the activation of the olefinic partner by a metal, the unfavorable thermodynamics associated with the addition of an enolate to a carbon—carbon multiple bond could be overwhelmed by using a strained alkene such as a cyclopropene derivative286. Indeed, Nakamura and workers demonstrated that the butylzinc enolate derived from A-methyl-5-valerolactam (447) smoothly reacted with the cyclopropenone ketal 78 and subsequent deuterolysis led to the -substituted cyclopropanone ketal 448, indicating that the carbometallation involved a syn addition process. Moreover, a high level of diastereoselectivity at the newly formed carbon—carbon bond was observed (de = 97%) (equation 191). The butylzinc enolates derived from other amides, lactams, esters and hydrazones also add successfully to the strained cyclopropenone ketal 78. Moreover, the cyclopropylzincs generated are stable and no rearrangements to the more stable zinc enolates occur after the addition. 

Two very elegant alkaloid syntheses basing on intramolecular cycloadditions of imino dienophiles have been published by Grieco and his coworkers. The preparation of ( )-eburnamonine 7-32 is very efficient since imine 7-31, available from (5-valerolactam in a straightforward sequence, is directly converted into the desired alkaloid 7-32 by aza Diels-Alder reaction and subsequent isomerisation of the newly formed double bond. (Fig. 7-8) [506],... 

Hosseinzadeh and coworkers reported a variant of this protocol that involves the use of KF/A1203 as base in the presence of Cul (10 mol%) and 1,10-phenanthroline (10 mol%) as ligand in refluxing toluene. Quantitative yields of the N-arylated products from the reactions of aryl iodides and benzamide, acetamide, acetanilide and 5-valerolactam were obtained in 1.5-12 h373. The general reaction protocol developed by Buchwald and coworkers for the amidation of aryl iodides and bromides has been used in several synthetic applications374 -378. 

Keywords lV-(aryloylmethyl)-<5-valerolactam, inclusion complex, photocycUza-tion, azetidine... 

Lactams are named in several ways. They are named as alkanolactams by the lUPAC substitutive system, such as 3-propanolactam, 4-butanolactam, 5-pentanolactam, and 6-hexano-lactam, respectively, for the 4-, 5-, 6-, and 7-membered rings, respectively. An alternate lUPAC method, the specialist heterocyclic nomenclature system, names these lactams as 2-azetidinone, 2-pyrrolidinone, 2-piperidinone, and hexahydro-2JS-azepin-2-one, respectively. These lactams are also known by the trivial names P-propiolactam, a-pyrrolidone (y-but5Tolactam), a-piperidone (5-valerolactam), and e-caprolactam, respectively. 

The following abbreviations have been employed for the various lactams BuL for y-butyrolactam (n = 3), NMBuL for N-methyl-y-butyrolactam, Val for 5-valerolactam (n = 4) NMVaL for N-methyl-5-valerolactam, CaL for -caprolactam (n = 5), and NMCaL for N-methyl- -caprolactam. 

The intermolecular addition of 5-valerolactam to 2,3-0-isopro-pylidene-D-glyceraldehyde is promoted hy a combination of 3 equiv each of TBDMS triflate and i-PrNEt2 (eq 17). Addition of nucleohases such as th3nnine, uracil, and 6-chloropurine is also effective under these conditions, with a similar preference for the awh -diastereomer. ... 

L5 6 5-Valerolactam a-Piperidone Pentane-5-lactam 2-Piperidinone 2-Piperidone... 

A mixture of ethyl 5-bromo-3-phenylvalerate and excess liq. NHg in benzene heated 15 hrs. in a sealed tube on a steam bath 3-phenyl-5-valerolactam. Y ca. 100%. A. Burger and A. Hofstetter, J. Org. Chem. 24, 1290 (1959). 

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