184110-47-2Relevant articles and documents
Scope and limitations of the catalytic asymmetric rearrangement of epoxides to allylic alcohols using chiral lithium amide bases/lithiated imidazoles
Oxenford, Sally J.,Wright, Jonathan M.,O'Brien, Peter,Panday, Narendra,Shipton, Mark R.
, p. 8315 - 8318 (2005)
The catalytic asymmetric rearrangement of functionalised cyclohexene and cyclopentene oxides has been studied using sub-stoichiometric amounts of a chiral lithium amide in combination with a stoichiometric amount of three different lithiated imidazoles. 1
TOTAL SYNTHESIS OF TRIOXACARCIN DC-45-A2 AND PREPARATION OF TRIOXACARCIN ANALOGS
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, (2016/07/05)
In one aspect, the present invention provides novel derivatives of trioxacarin analogs of the formula (I) wherein the variables are as defined herein. The application also provides compositions, methods of treatment, and methods of synthesis thereof.
Total synthesis of trioxacarcin DC-45-A2
Nicolaou, K. C.,Cai, Quan,Qin, Bo,Petersen, Mette T.,Mikkelsen, Remi J. T.,Heretsch, Philipp
, p. 3074 - 3078 (2015/07/01)
An enantioselective total synthesis of trioxacarcin DC-45-A2 (1) featuring a novel Lewis acid-induced cascade rearrangement of epoxyketone 6 to forge the polyoxygenated 2,7-dioxabicyclo[2.2.1]heptane core of the molecule is described.
Chiral lithium amide base-mediated rearrangement of meso-cyclohexene oxides: Asymmetric synthesis of amino- and aziridinocyclohexenols
O'Brien, Peter,Pilgram, Christopher D.
, p. 523 - 534 (2007/10/03)
Two different chiral lithium amide base routes for the synthesis of amino- and aziridino-containing cyclohexenols have been explored. The first strategy involved the diastereoselective preparation of novel meso-aziridinocyclohexene oxides and their subsequent enantioselective rearrangement using chiral bases. In this approach, the diphenyl-phosphinoyl nitrogen protecting group proved optimal and aziridinocyclohexenols of 47-68% ee were obtained. Of particular note was the smooth rearrangement of the epoxide to an allylic alcohol in the presence of an aziridine: under optimised chiral base conditions, the aziridine remained essentially unaffected. A second more straightforward strategy for introduction of an amino functionality was also investigated: (1S,4R,5S)- and (1R,4R,5S)-4,5-bis(tert-butyldimethylsilyloxy)cyclohex-2- enols, readily prepared in >95% ee using a chiral base approach, were subjected to Mitsunobu substitution using a sulfonamide and Overman rearrangement.
Optimisation of enantioselectivity for the chiral base-mediated rearrangement of bis-protected meso-4,5-dihydroxycyclohexene oxides: Asymmetric synthesis of 4-deoxyconduritols and conduritol F
De Sousa, Simon E,O'Brien, Peter,Pilgram, Christopher D
, p. 4643 - 4654 (2007/10/03)
A strategy based on diastereoselective epoxidation of a cyclohexene followed by chiral lithium amide-mediated epoxide rearrangement has been used to synthesise an allylic alcohol building block of >95% ee. The key step is the enantioselective rearrangement of a bis-protected meso-4,5-dihydroxycyclohexene oxide. A range of protecting groups and chiral base structures were surveyed in order to find the optimum protocol for high enantioselectivity. Using a tert-butyldimethylsilyloxy protecting group and a norephedrine-derived chiral base, a 93% yield of an allylic alcohol of >95% ee was achieved. To demonstrate the synthetic utility, this allylic alcohol was subsequently transformed into 4-deoxyconduritols and (+)-conduritol F.
Enantioselective rearrangement of a meso-cyclohexene oxide using norephedrine-derived chiral bases
Colman, Bob,De Sousa, Simon E.,O'Brien, Peter,Towers, Timothy D.,Watson, Will
, p. 4175 - 4182 (2007/10/03)
Using a chiral base from a norephedrine-derived diamine, the enantioselective rearrangement of a meso-cyclohexene oxide can be performed in 94% yield and with 94% enantioselectivity. The enantioselectivity is lower (86% ee) with the diastereoisomeric chiral base. In order to prepare the diastereoisomeric chiral base, a potentially useful way of converting norephedrine into norpseudoephedrine was developed.
A new norephedrine-derived chiral base for epoxide rearrangement reactions
De Sousa, Simon E.,O'Brien, Peter,Steffens, H. Christian
, p. 8423 - 8425 (2007/10/03)
The conversion of (1R,2S)-norephedrine into a novel chiral diamine (83% yield, simple two step synthesis) and its use as a chiral base in two epoxide rearrangement reactions is reported. Rearrangement of a 4,5-disubstituted cyclohexene oxide and of a 4-aminosubstituted cyclopentene oxide generated allylic alcohols of >90% ee. These results represent the highest levels of enantioselectivity reported to date for such substrates.
Chiral lithium amide base-mediated rearrangement of bis-protected meso-4,5-dihydroxy cyclohexene oxides: Enantioselective synthesis of (4R,5S) and (4S,5R)-4,5-bis(tert-butyldimethylsilyloxy)cyclohex-2-enone
O'Brien, Peter,Poumellec, Pierre
, p. 2435 - 2441 (2007/10/03)
The asymmetric synthesis of (4R,5S)- and (4S,5R)-4,5-bis(tert-butyldimethylsilyloxy)cyclohex-2-enone are described. Such bis-protected enones are useful intermediates in synthesis, and compounds with (4S,5R)-stereochemistry have previously been prepared from D-(-)-quinic acid. This paper reports the first synthesis of enones with (4R,5S)-stereochemistry. The route to the bis-protected enones involves chiral base-mediated rearrangement of meso-cyclohexene oxides to allylic alcohols followed by PDC oxidation. Two new chiral base reactions are described: rearrangement of a trans-epoxide generates an allylic alcohol of 76% ee (93% yield) whilst that of a cis-epoxide produces an allylic alcohol of 92% ee (38% yield); suggestions for the observed differences in yield and enantioselectivities are proposed.
Chiral base-mediated rearrangement of meso-cyclohexene oxides to allylic alcohols
O'Brien, Peter,Poumellec, Pierre
, p. 8057 - 8058 (2007/10/03)
Highly enantiomerically enriched allylic alcohols have been generated by rearranging single diastereomers of meso-cyclohexene oxides using a homochiral lithium amide base. PDC oxidation of each allylic alcohol product affords a different enantiomer of a synthetically useful cyclohexenone.
