Lactams, diallylation

The reaction can be applied to allyl malonates. Alkylation of diallyl mal-onate (734) with bromoacetate and acetoxymethylation afford the mixed triester 735. Treatment of the tricster 735 with Pd catalyst affords allyl ethyl itaconate (736). In a similar way, a-methylene lactone and the lactam 737 can be prepared[462]. 

Carbacephem 69 is obtained in excellent yield by ring-closure of the 1,4-diallyl-P-lactam 68 by a metathesis reaction in the presence of a ruthenium catalyst <99JCS(P1)1695>. Annulated carbacephams 71 is obtained by cyclization of the piperidine 70 in the presence of a 2-chloro-l-methylpyridinium salt <98JOC8170>. 

A sequence of reactions that was recently reported by Hanessian and Alpegiani nicely illustrates how the allylstannane method is useful for functionalization of complex, sensitive substrates and, more generally, how stereochemistry can be controlled in radical addition reactions (Scheme 40).138 Dibromo- 3-lac-tam (25) can be monoallylated with a slight excess of allyltributylstannane and then reduced with tributyltin hydride to provide 3-allylated (3-lactam (26) (the acid salt of which shows some activity as a 3-lactamase inhibitor). Stereochemistry is fixed in the reduction step hydrogen is delivered to the less-hindered face of the radical. Alternatively, monodebromination, followed by allylation, now delivers the allyl group from the less-hindered face to provide stereoisomer (27). Finally, allylation of (25) with excess allylstannane produces the diallylated product (not shown). 

In this presentation, reductive a-allylation of indoles and reductive diallylation of lactams with allylic boranes as well as a new way to isoquinuclidine structures are described. 

Lactams containing N-H bond are smoothly transformed into the corresponding 2,2-diallylated nitrogen heterocycles 12 and 13 on heating with trialyl- or trimethallylborane, followed by treatment with methanol and alkali solution. 

A,A-Disubstituted amides can be converted to alkynyl ketones by treatment with alkynylboranes RCONR2 + (R C=C)3B RCOC=CR. Lactams react with triallylborane to give cyclic 2,2-diallyl amines after treatment with methanol, and then aqueous hydroxide. Triallylborane reacts with the carbonyl group of lactams, and after treatment with methanol and then aqueous NaOH gives the... 

Related 1,2-additions to imines in the -lactam area employing organocuprates have also met with considerable success. Net substitution reactions, proceeding via intermediate imino derivatives, have been achieved with lithium diallyl- and dialkyl-cuprates on educts such as (105) and (106). When a stereochemical label is present as in (107) and (108), the major products reflect trans addition to imines (109) and (110), respectively (Scheme 18). 

Homoallylamines. A synthesis of homoallylamines from nitriles consists of consecutive treatment with diisobutylaluminum hydride and triallylamine. Lactams undergo deoxygenative diallylation. ... 

Other examples of the use of intramolecular Diels-Alder reactions in preparative chemistry have appeared the o-quinodimethane (186), produced as a transient intermediate in the pyrolysis of the analogous benzocyclobutene, cyclizes to give (187 65%), the desulphurization of which (Raney nickel) affords a potential intermediate for the preparation of tetracyclic diterpenes. Elevated temperatures result in the isomerization of (188) into the internal [4 -I- 2] adduct (189) in which it is clear that a cyano-group has acted as a dienophile (189) is the result of a subsequent double-bond shift, and the structure was validated by crystallographic structure analysis. Bridged y-lactams have been successfully prepared by the intramolecular Diels-Alder reactions of NN-diallyl- and iV-(l,l-dimethylprop-2-yn-l-yl)amides of various penta-2,4-diene carboxylic acids. Thus, pyrolysis of (190) gave an 80%... 

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