Reactions of tertiary allylamines with dimethyl acetylenedicarboxylate

Abstract

The reaction of some tertiary allylamines with dimethyl acetylenedicarboxylate in acetonitrile results in the formation of 1 : 1 adducts via [3,3] rearrangement of the ally1 group from nitrogen to carbon.Tertiary amines catalyse the nucleophilic addition of species HX to activated acetylenes.' In some other cases, adducts incorporating the amine moiety are obtained as the result of C-N bond cleavage. Winterfeldt has described a variety of such reactions involving the tertiary amino-ester (la) and -ketones (lb) and (2) with methyl propiolate to give p-aminocrotonates (3a) and (3b).' The formation of N-ethylpyrrole derivatives from tertiary amines (lb) and (lc) and acetylene esters involves loss of the second N-ethyl group in each case. Similarly triethylamine is reported to add to dimethyl acetylenedicarboxylate (DMAD) in the presence of a proton source to give compound (4a), for which the maleate configuration, not assigned at the time, is correct by comparison of spectral data with those of analogous corn pound^.^^^ N-Benzylaziridine catalyses the trimerisation of DMAD in aprotic solvents, but in t-butyl alcohol a 1: 1: 1 adduct (4c) is obtained through opening of the aziridine ring.' Meo2c&ozMe Et ,NCH2 R ( 1 ) a; R = CH,CO,Et H NR' R' 1 2 b; R = COPh ( 4 ) a; R = R = E t c; R = C02Me b; R ' , R 2 = (CH,), 1 C; R = CHZPh, R2= C H 2 C H 2 0 8~' d; R'= R2= Me 1 2 e; R , R =(CH212 1 2 1 2 ( C N C ti 2 c H 2)0 f ; R , R = CHzCH=CHCH2 9; R , R = (CH,),R1R2NCH=CHC02Me 1 2 1 ( 3 ) a; R = R = Et b; R , R 2 = (CH215 the same derivative (9b). Authentic samples of the by-products (4a) and (4b) were prepared from DMAD with diethylamine and piperidine, respectively, and similarly converted into the 2,4-dinitrophenylhydrazone derivative (9a). Catalytic hydrogenation of the adduct (7a) gave the corresponding propyl compound (8), which was characterised both as the 2,4-dinitrophenylhydrazone (9d), and by degradation to 2-oxohexanoic acid (Scheme 2). Me02C , C0,Me \ %+ , R1 R'R2NCH2CH=CHR3 -R37(&J,R2 ( 6 ) ( 5 ) a ; R 1 2 = R = E t , R 3 = H c ; R 1 = R 2 = Et, R 3 = Me I b; R', R2 = (CH2I5, R 3 = H Pd I H2 ( 7 a I -CH 1 3 ( 7 ) a ; R = R2= Et, R = H b; R', R 2 = (CH215, R 3 = H 1 c; R = RZ= Et, R3= Me Scheme 1. M e o z c~c o 2 N e -H~O + BuCOC02H Pr NEt, ( 8 1 Scheme 2.Me0,C COzMe Me02C \ /CO2Me Results and DiscussionWe have examined the addition of tertiary allylic amines to DMAD. Although no reaction occurs between allyldiethylamine (5a) and DMAD in dry ether, these compounds react readily in acetonitrile at room temperature to give the 1: 1 adduct (7a) together with smaller amounts of the aminomaleate ( 9 a; = (4a). The proportion of (4a) increased if water was added to the product (7a) even when thoroughly dry acetonitrile was used. the 1: 1 adduct (7b) and a smaller amount of (4b). The constitution of the adducts (7a) and (7b) was proved from their 'H n.m.r. and mass spectra and by hydrolysis in the presence of a x ; : //C -CH Me 2 , 4 -( 0 ,~ ),C~H,NHN ' R (10) system, but it still amounted to a small percentage of the m...

Bulk Gold-Catalyzed Reactions of Diazoalkanes with Amines and O2 to Give Enamines

“…The 1 H NMR spectrum of (Z)-9 is the same as that reported in the literature [60] for this compound. The (E)-selectivity for the reaction of EDA with secondary amines is very similar to the reactions of dimethyl acetylenedicarboxylate (DMAD) with amines in which the (E)-configuration of the enamine esters was shown to be thermodynamically preferred [56][57][58][59]. The dominant (Z)-selectivity for primary amines is presumably due to the formation of a hydrogen bond between the free NH and the carbonyl oxygen as shown in Scheme 1, which was proposed by Iwanami as the reason for the formation of (Z)-enamines from the reactions of DMAD with primary amines [61].…”

“…10) (see Electronic Supplementary Material). The configurations of the (E)-and (Z)-isomers were established by comparison of their 1 H NMR spectral data with those of the dimethyl analogs reported by Vernon [58,59], Dolfini [62], and Saidi [63]. The (E)-enamines show a singlet near 4.7 ppm for the olefinic proton, while the (Z)-isomers show a singlet at about 5.1 ppm.…”

“…Enamine products were identified by comparison of their 1 H NMR spectra with those of authentic samples. These samples were prepared [56][57][58][59] as described in the Electronic Supplementary Material where 1 H and 13 C NMR and mass spectral data for all of the products are also given.…”

Phospha-Claisen Type Reactions at Frustrated Lewis Pair Frameworks

“…1,2 There had been reports that simple phosphanes such as e.g. 1,2 There had been reports that simple phosphanes such as e.g.…”

The reactions of simple dimethylallylamines with dimethyl acetylenedicarboxylate. Formation of 1-dimethylamino-2-allylmaleates via formal allyl transfer

“…NOTE ADDED IN PROOF: After this paper was accepted we became aware of recent, closely related work by Kandeel and Vernon (41).…”