Cinnamylic ether

Pd(Ph3P)4, RS02Na, CH2CI2 or THF/MeOH, 70-99% yield. These conditions were shown to be superior to the use of sodium 2-ethylhexanoate. Methallyl, crotyl, and cinnamyl ethers, the Alloc group, and allylamines are all efficiently cleaved by this method. ... 

The MNDO structures of intermediates and transition states for the cleavage of benzyl and cinnamyl ethers through anion-radical routes and dianion routes involving CIPs (contact ion pairs) and IIPs (isolated nonsolvated ion pairs) are given in Figure 18. 

FIGURE 17a. Alternative routes for vinylogous birch reductive cleavage of cinnamyl ether promoted by lithium naphthalenide. Reprinted with permission from Reference 22. Copyright 1996 American Chemical Society... 

Oxidation of aUybenzene. Oxidation of allylbenzcne with this reagent and an alcohol results exclusively in a mms-cinnamyl ether (equation I). 

A ceric ammonium nitrate (CAN) mediated stereoselective cyclization of epoxypropyl cinnamyl ethers 352 provides a facile route to 3,4,5-trisubstituted tetrahydropyran derivatives 353 (Equation 149) <2004TL2413>. 

Farina has shown that the reaction of 129 with cinnamyl chloride in THF with Pd2(dba)3 and tri-(2-furyl)phosphine as precatalytic system, results in incomplete formation of the C-allylated 130a, the isomeric cinnamyl ether of 129 being also isolated (91JA9585). 

Cinnamyl ethers are carbolithiated to give intermediates similar to 37, but without the additional lithium cation of the alkoxide substituent they presumably exist in a structure closer to 46. The products of deuteration and carboxylation of this organolithium have anti... 

The electron-rich oxygen atom of a secondary amide derivative of cinnamic acid can be as effective as that of a cinnamyl ether or alcohol in directing anr/-Michael additions to some amide Michael acceptors. For example, BuLi adds to the amide 51 to give a 90 10 ratio of anti-Michael Michael addition products 52 53.31 With the alkyne54 the effect is even more pronounced MeLi gives solely the anti-Michael product 55. These reactions are however very sensitive to starting material and reagent structure. 

Electrolysis Hg electrode, —2.45 V, 54-80% yield. Cinnamyl ethers are also cleaved, but at more negative potentials. 

The only kinetic study of acid-catalyzed isomerization of a simple allylic ether was published by Braude and Gore who found that methyl a-phenylallyl ether isomerizes to methyl cinnamyl ether in anhydrous dioxane containing either boron trifluoride or hydrogen chloride. At 25°C, the ether is a quarter to an eighth as reactive as the corresponding alcohol. 

The cinnamyl ethers were treated with an iridium catalyst to furnish the corresponding vinyl ethers (Eq. 3.1.12). The utility of this catalyst was demonstrated in the stereoselective synthesis of aUyl vinyl ethers. 2,3,3-Trimethyl-4-pentenal was obtained in 51% yield when the isomerization of the diaUyl ether to give the aUyl vinyl ether was followed by heating to proceed the Claisen rearrangement (Eq. 3.1.13). 

Katsuki et al. reported the Claisen rearrangement of aryl cinnamyl ether 39 for the preparation of a chiral salen complex [39]. They noted that the addition of an equimolar amount of CaCOj is effective to minimize the para rearrangement. 

Later, Hajra and Sinha reported an enantioselective tandem aziridoar-ylation of aryl cinnamyl ethers to give the corresponding M-sulfonyl-pro-tected frans-3-amino-4-aiylchromans using a combination of two copper catalysts. The first step of the sequence involved the asymmetric azir-idination of the aryl cinnamyl ether catalysed by a copper catalyst of a chiral... 

A copper-catalyzed enantioselective aziridination of aryl cinnamyl ethers and intramolecular arylation of the in situ generated tethered aziridine was developed by Hajra and Sinha. This method provides an easy access of N-sulfonyl-protected fra s-3-amino-4-arylchromans with high regio-, diastereo- (dr > 99 1), and enantioselectivity (ee up to 95%) (Scheme 8.113). Three C(sp )-H bonds were activated in this transformation under this Cu(0Tf)2/Cu(C10 )2-6H20 catalyst system. The major side reaction is the C-H insertion of nitrene at the O-CH2 unit followed by oxidative cleavage [188]. 

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