224967-43-5Relevant articles and documents
Silver(I)-catalyzed ring-contractive rearrangement: A new entry to 5-alkylidene-2-cyclopentenones
Zhao, Liang,Wang, Jinlian,Zheng, Hongyan,Li, Yun,Yang, Ke,Cheng, Bin,Jin, Xiaojie,Yao, Xiaojun,Zhai, Hongbin
supporting information, p. 6378 - 6381 (2015/01/09)
A novel silver(I)-catalyzed ring-contractive rearrangement of 5-substituted 6-diazo-2-cyclohexenones has been developed, providing a new and efficient access to 5-alkylidene-2-cyclopentenones. The AgOTf-catalyzed reaction proceeds through metal-carbenoid formation followed by endocyclic allyl [1,2] migration with excellent stereoselectivity and broad substrate scope.
Lewis acid promoted oxidative rearrangement of tertiary allylic alcohols with the PhIO/TEMPO system
Vatèle, Jean-Michel
experimental part, p. 1785 - 1788 (2009/04/07)
A mild and environmentally friendly method for Lewis acid catalyzed oxidative rearrangement of tertiary allylic alcohols to β-disubstituted enones by the TEMPO/PhIO system is described. Bismuth triflate was found to be the most efficient catalyst for the majority of the substrates tested except for tertiary vinyl carbinols which could be transformed to enals in fair yields only when Re2O7 was used as catalyst. A plausible mechanism for this oxidative rearrangement is discussed. Georg Thieme Verlag Stuttgart.
Synthesis of optically active 5-(tert-butyldimethylsiloxy)-2- cyclohexenone and its 6-substituted derivatives as useful chiral building blocks for the synthesis of cyclohexane rings. Synthesis of carvone, penienone, and penihydrone
Hareau, Georges P.-J.,Koiwa, Masakazu,Hikichi, Shinichi,Sato, Fumie
, p. 3640 - 3650 (2007/10/03)
Optically active 5-(tert-butyldimethylsiloxy)-2-cyclohexenone (1) and its 6-substituted derivatives 2a,b were synthesized from the readily available optically active ethyl 3-(tert-butyldimethylsiloxy)-5-hexenoate (4), where the Ti(II)-mediated intramolecular nucleophilic acyl substitution reaction and the FeCl3-mediated ring expansion reaction of a 1- hydroxybicyclo[3.1.0]hexane are the key reactions. The enone 1 reacted with higher-order cyanocuprates with excellent diastereoselectivity to afford the trans-addition products, trans-13, in excellent yields. The reaction of 1 with lower-order cyanocuprates proceeded with moderate to excellent syn- selectivity to afford cis-13. Treatment of trans- and cis-13 with DBU (1,8- diazabicyclo[5.4.0]undec-7-ene) or catalyst p-TSA (p-toluenesulfonic acid) resulted in a β-elimination reaction to furnish the corresponding optically active 5-substituted-2-cyclohexenones 14. The 1,4-addition reaction of 2a and 2b with organocy-anocuprates followed by treatment of the resulting 20 with DBU provided the 2,5-disubstituted-2-cyclohexenones 19 with excellent ee. The conversion of 14 into the 3,5-disubstituted-2-cyclohexenone 22 has also been carried out via 1,2-addition of alkyllithium onto the carbonyl group and the following oxidation with PCC (pyridinium chlorochromate). Similarly, the conversion of 19 into 2,3,5-trisubstituted-2-cyclohexenones 24 has been carried out. A highly efficient, first total synthesis of penienone 25 and penihydrone 26 has been accomplished. Thus, the 1,4-addition reaction of 1 with the (E,E)-1,3-heptadienyl cyanocuprate and consecutive trap of the resulting copper enolate with formaldehyde gave 28, which upon treatment with DBU or Pyr · HF yielded 25 and 26, respectively. An efficient synthesis of both enantiomers of carvone starting from (S)-20ab has been also accomplished.
