966-47-2Relevant articles and documents
A concise route to (+)-estrone
Tanaka, Keigo,Nakashima, Hiromi,Taniguchi, Takahiko,Ogasawara, Kunio
, p. 1915 - 1917 (2000)
(Formula presented) A concise route to the Torgov diene, the key intermediate of estrone, has been devised using a chiral dioxycyclopentenone as the starting material by employing a sequence of five steps of reactions involving a Lewis acid-mediated Diels-Alder reaction with Dane's diene.
Organocatalytic asymmetric formation of steroids
Halskov, Kim Soholm,Donslund, Bjarke S.,Barfuesser, Sebastian,Jorgensen, Karl Anker
, p. 4137 - 4141 (2014)
A novel and simple one-step approach for the construction of optically active steroids in a highly stereoselective manner by using organocatalysis is presented. The reaction of (di)enals with cyclic dienophiles in the presence of a TMS-protected prolinol catalyst leads to the construction of important 14 β-steroids. This new reaction allows an easy access to optically active steroids with a variety of substituents in the A ring in high yields and up to greater than 99 % ee. The reaction has been extended to include the construction of B- and D-homosteroids as well as steroids containing heteroatoms in the B ring. The angular substituent at C13 can be varied and alkyl, ester, and sulfone functionalities are introduced with excellent stereoselectivities. Simple synthetic procedures provide access to a range of naturally occurring steroids such as estrone and related analogues. Organocatalysis made it possible: The reported methodology gives 14 β-steroids, displaying a broad generality, in one step, and includes various substituents on the A ring, variations of the B ring, hydroxy or alkyl substituents in the 12-position of the C ring, and different substituents in the angular position at C13. Furthermore, the developed reaction concept includes reactions with quinones to form D-homosteroids in excellent yields and stereoselectivities.
Desymmetrization of cyclic 1,3-diketones via Ir-catalyzed hydrogenation: An efficient approach to cyclic hydroxy ketones with a chiral quaternary carbon
Gong, Quan,Wen, Jialin,Zhang, Xumu
, p. 6350 - 6353 (2019/07/04)
We herein report an efficient method to synthesize cyclic hydroxy ketones with a chiral quaternary center. Catalyzed by an Ir/f-ampha complex, cyclic α,α-disubstituted 1,3-diketones were hydrogenated, giving mono-reduced products with both high enantiosel
Catalytic asymmetric torgov cyclization: A concise total synthesis of (+)-estrone
Prevost, Sebastien,Dupre, Nathalie,Leutzsch, Markus,Wang, Qinggang,Wakchaure, Vijay,List, Benjamin
supporting information, p. 8770 - 8773 (2014/08/18)
An asymmetric Torgov cyclization, catalyzed by a novel, highly Bronsted acidic dinitro-substituted disulfonimide, is described. The reaction delivers the Torgov diene and various analogues with excellent yields and enantioselectivity. This method was applied in a very short synthesis of (+)-estrone.
Enantioselective synthesis of (+)-estrone exploiting a hydrogen bond-promoted Diels?Alder reaction
Weimar, Marko,Duerner, Gerd,Bats, Jan W.,Goebel, Michael W.
supporting information; experimental part, p. 2718 - 2721 (2010/07/17)
Starting from Danes diene and methylcyclopentenedione, (+)-estrone is synthesized along the Quinkert?Dane route in 24% total yield. The key step is an enantioselective Diels?Alder reaction promoted by an amidinium catalyst as efficiently as by a traditional Ti-TADDOLate Lewis acid.
Highly enantioselective [4 + 2] cycloaddition reactions catalyzed by a chiral N-methyl-oxazaborolidinium cation
Canales, Eda,Corey
supporting information; experimental part, p. 3271 - 3273 (2009/05/27)
(Chemical Equation Presented) The reaction of lithium aryl borohydrides with salts of β-amino alcohols provides a new route for the synthesis of oxazaborolidines. This method also leads to the first synthesis of hitherto elusive N-methyl oxazaborolidine c
Formal enantioselective synthesis of (+)-estrone
Soorukram, Darunee,Knochel, Paul
, p. 1021 - 1023 (2007/10/03)
(Chemical Equation Presented) A formal total synthesis of (+)-estrone (4% overall yield; ca. 12 steps) could be achieved via the Torgov diene. An asymmetric allylic substitution is the key step for the construction of the chiral quaternary carbon center of a synthetic intermediate which was converted in four steps to the Torgov diene.
Conversion of Torgov's synthesis of estrone into a highly enantioselective and efficient process
Yeung, Ying-Yeung,Chein, Rong-Jie,Corey
, p. 10346 - 10347 (2008/03/12)
A very direct and efficient conversion of the achiral Torgov diketone into the natural form of O-methyl estrone is described. Copyright
Simple, Catalytic Enantioselective Syntheses of Estrone and Desogestrel
Hu, Qi-Ying,Rege, Pankaj D.,Corey
, p. 5984 - 5986 (2007/10/03)
Highly enantioselective and very short syntheses of the bioactive forms of estrone (3) and desogestrel (4) are described using a chiral oxazaborolidinium catalyst (2) in the key initial step. Enantiomerically pure estrone was synthesized in eight steps from the readily available starting materials diene 5 and α,β-enal 6 via intermediates 8 and 9. Desogestrel was synthesized using a similar strategy from diene 5 and α,β-enal 11 via intermediates 12-17. The efficient syntheses of the chiral catalyst 2 and its enantiomer are also presented. Copyright
Enantioconvergent synthesis of (+)-estrone from racemic 4-tert-butoxy-2-cyclopentenone
Sugahara, Tsutomu,Ogasawara, Kunio
, p. 7403 - 7406 (2007/10/03)
(+)-Estrone has been synthesized in an enantioconvergent manner from racemic 4-tert-butoxy-2-cyclopentenone via contrasteric Diels-Alder reaction and lipase-mediated kinetic transesterification as the key steps.
