Desymmetrization of Cyclohexa-1,4-dienes − A Straightforward Route to Cyclic and Acyclic Polyhydroxylated Systems

Abstract

A straightforward route to polyols, amino polyols, polysubstituted lactols and lactones from readily available arenes has been devised. It uses a three-or four-step sequence involving a Birch reduction of the arene, followed by desymmetrization through dihydroxylation or aminohydroxylation and, lastly, ozonolysis of the remaining olefin. Depending on the ozono-

Scalable and safe synthetic organic electroreduction inspired by Li-ion battery chemistry

“…1E; for a complete listing, see Supplementary Materials), of which select efforts are summarized in entries 1-4. (12,13,15,36,42,43,48) To help probe the functional-group tolerance of these prior works, we opted for phenyl ethanol (3) as a model substrate. The conditions reported by Kashimura (15) were chosen as a basis set from which to launch more extensive optimization (entry 4); however, the limitations of that state-of-theart were clearly demonstrated in that 3's alcohol moiety completely shut down reactivity under Kashimura's conditions.…”

“…Accordingly, the current study began with an extensive evaluation of this prior art, of which select efforts are summarized in entries 1 to 4 of Fig. 1E (see supplementary materials for a complete listing) (12,13,15,36,42,43,48). To help probe the functional-group tolerance of these previous works, we opted for phenyl ethanol (3) as a model substrate.…”

Diastereoselective alkylation reactions of 1-methylcyclohexa-2,5-diene-1-carboxylic acid

“…Cyclohexa-1,4-dienes are versatile intermediates in synthetic organic chemistry, most commonly prepared by various permutations of the Birch reduction. 1 In particular, with appropriate substitution patterns the two double bonds are either enantiotopic (achiral cyclohexadienes) or diastereotopic (chiral cyclohexadienes) and therefore their elaboration can lead to the formation of one or more new stereogenic centres 2 using either inter- 3 or intramolecular 4 transformations.…”

“…Early introduction of R 1 is preferable, since the desymmetrisation process to form 6 can proceed with the selective formation of four stereogenic centres in a single step, controlled by a stereogenic substituent R 3 . In fact, by using a desymmetrisation process which gives reaction at both cyclohexadiene doublebonds, it is possible to form six contiguous stereogenic centres with complete stereoselectivity in a single step, demonstrating the power of this approach.…”

Iodocyclization Reactions for the Desymmetrization of Cyclohexa-1,4-dienes

“…The ease of preparation of hydroxymethyl-substituted cyclohexadienes stems from the use of methyl cyclohexa- 2,5-diene-1-carboxylate as a starting material and offers considerable opportunities for further elaboration of the products. However, this is not required for successful iodocyclization, and substrates 12a − c lacking this group were prepared by deprotonation of cyclohexa-1,4-diene followed by reaction with an epoxide. These compounds all undergo a completely diastereoselective iodocyclization reaction to give products 13a − c as shown in Scheme .…”