67845-50-5Relevant articles and documents
Synthesis of (S)- and (R)-sporochnol by using the allylic substitution of the secondary allylic picolinate
Kobayashi, Yuichi,Sugihara, Yusuke,Tojo, Toshifumi,Ozaki, Takuri
, p. 47 - 54 (2017/03/14)
The allylic substitution of secondary allylic picolinates and copper reagents for the construction of a quaternary carbon was applied to synthesis of sporochnol. The enantiomerically enriched allylic picolinate (R)-5 was synthesized through the asymmetric hydrogen transfer of acetylene ketone 11 and the Pd-catalyzed methylation of the iodoallylic alcohol 16a. The key allylic substitution of the allylic picolinate (R)-5 with 4-MeOC6H4MgBr/Cu(acac)2 (2:1) proceeded with 95% chirality transfer with 98% regioselectivity to afford anti SN2' product 6 in 89% yield, which was converted to the methyl ether of unnatural (R)-sporochnol. Similarly, the methyl ether of (S)-sporochnol (the natural form) was synthesized.
Allylic substitution for construction of a chiral quaternary carbon possessing an aryl group
Feng, Chao,Kobayashi, Yuichi
, p. 3755 - 3766 (2013/06/05)
Phenylcopper reagents derived from 2:1 PhMgBr/Cu(acac)2 and 3:1:1 PhMgBr/Cu(acac)2/ZnI2 were found to be highly reactive and regioselective in the allylic substitution of γ,γ- disubstituted secondary allylic picolinates designed for construction of a quaternary carbon, whereas the previous 2:1 ArMgBr/CuBr·Me2S reagent and that with ZnX2 were unsuccessful. The generality of the ArMgBr/Cu(acac)2 reagent was examined with enantiomerically enriched allylic picolinates, which furnished quaternary carbons with high efficiency in >92% regioselectivity and >97% chirality transfer. Two cyclohexanes with a quaternary carbon were synthesized by using these reagents.
Highly stereoselective C-C bond formation by rhodium-catalyzed tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor carbenoids and chiral allylic alcohols
Li, Zhanjie,Parr, Brendan T.,Davies, Huw M. L.
supporting information; experimental part, p. 10942 - 10946 (2012/08/07)
The tandem ylide formation/[2,3]-sigmatropic rearrangement between donor/acceptor rhodium carbenoids and chiral allyl alcohols is a convergent C-C bond forming process, which generates two vicinal stereogenic centers. Any of the four possible stereoisomers can be selectively synthesized by appropriate combination of the chiral catalyst Rh2(DOSP)4 and the chiral alcohol.
