Hydrolysis transannular

The above is a typical example of a transannular hydride shift. The 1,2-diol is formed by a normal epoxide hydrolysis reaction (10-7). For a discussion of 1,3 and... 

Hydrolysis of optically pure bromide 100 a in dioxane/water gives the optically pure alcohol. This is consistent with the transannular p-xylylene ring participating in carbonium ion formation only through tz-g charge delocalization (iz-c resonance) of the type 104 rather than by direct participation in replacement of bromide via a transannularly bridged ion such as 102a. In the latter case, racemization would be expected to take place ... 

The chiral organocopper compound (186) adds diastereoselectively to 2-methyl-2-cyclopentenone, allowing the preparation of optically active steroid CD-ring building blocks (Scheme 68).202-204 A related method was applied to a synthesis of the steroid skeleton via an intramolecular (transannular) Diels-Alder reaction of a macrocyclic precursor.203 Chiral acetone anion equivalents based on copper azaeno-lates derived from acetone imines were shown to add to cyclic enones with good selectivity (60-80% ee, after hydrolysis).206-208 Even better ee values are obtained with the mixed zincate prepared from (187) and dimethylzinc (Scheme 69). Other highly diastereoselective but synthetically less important 1,4-additions of chiral cuprates to prochiral enones were reported.209-210... 

Chloroprene is dimerized to 54 when heated. When the dimer is treated with sulfuric acid, hydrolysis to 1,4-cyclooctanedione occurs and this diketone experiences transannular closure under the reaction conditions.100 ... 

Even the cyclopropane-diazonium ions (4<59)366 367 and (474)368 decompose with participation by the double bond. The hydrolysis of bicyclo [4.3.1] dec-6-en-l-yl p-nitrobenzoate (475) is accelerated by a factor of 120 and affords, inter alia, the tricyclic alcohols (47<5)369. A related case of transannular participation, leading to ion pair return, was observed with 5-cyclodecen-l-yl p-nitrobenzoate (7 >4)112 (Section 4.2.3). 

Transannular participation of n-bonds takes place in the solvolysis of esters of (Z)-cyclooct-3-enol to give bicyclic derivatives containing three-membered rings. Thus, acetolysis of 4-(4-bromophenylsulfonyloxy)cyclooctene followed by hydrolysis of the product mixture gave endo-and exo-bicyclo[5.1.0]octan-2-ol (1), in 39 and 13% yield, respectively. The predominant formation of the cntfo-bicyclooctanol is consistent with a concerted process. ... 

In further work, Johnson investigated the interception of ketal hydrolysis by a transannular amine reaction. The debenzylated protected intermediate (61) was cyanomethylated in 85% yield [Eq. (21)]. Because of the reduced... 

Cyclopentanol ene type products have been obtained in stepwise reactions. Treatment of (223) with SnCU gives (222) in 42% yield. Cyclization with TiCU affords chloro alcohol (224) in 80-90% yield.85 Treatment of (225) with formic acid at 45 °C results in loss of methanol to give the unsaturated ketone, followed by transannular Prins reaction and loss of a proton to give, after hydrolysis of formate esters,... 

Alkaline hydrolysis of the acetoxy or phthalimido substituents in several derivatives of (16) affords pyrazole derivatives in ca. 60-75 /o yield, apparently via transannular ring closure, followed by alcoholysis and elimination, as shown for the acetoxy derivatives (16 Ar = Ar = Ph, X = OAc, Y = Cl, SPh). Isolation of the intermediate bicyclic enone upon acidic hydrolysis of the SPh derivative provides strong support for this mechanistic proposal (Scheme 7) <87CL157>. 

Aq. 54%-peroxyacetic acid containing Na-acetate added dropwise with stirring at 0° during 1 hr. to cis-frans-cyclodeca-l,5-diene in methylene chloride, and the product isolated after 3 hrs. monoepoxide (Y 80%) added dropwise with stirring during 1 hr. to boiling water, and heated an additional 2 hrs. at 100° rac-(IS 4S 9R) (IR 4R 9S)-cis-decaline-l,4-diol (Y 93%). —The hydrolysis is transannular and stereospecific. W. Dittmann and F. Stiirzenhofecker, A. 688, 57 (1965). 

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