Studies Toward the Enantiospecific Total Synthesis of Rhodexin A
作者:Michael E. Jung、Mikhail Guzaev
DOI:10.1021/jo400909t
日期:2013.8.2
enantiospecific total synthesis of rhodexin A via a very hindered inverseelectrondemandDiels–Alderreaction are described. The C8-diastereomer of the fully elaborated tetracyclic core of rhodexin A, 23, was prepared in good yield and excellent selectivity using as the key step the stepwise Diels–Alderreaction of the very hindered dienone 3 and the silyl enolether 4 catalyzed by the very strong Lewis
Synthesis of Highly Substituted Cyclohexenes via Mixed Lewis Acid-Catalyzed Diels−Alder Reactions of Highly Substituted Dienes and Dienophiles
作者:Michael E. Jung、David Ho、Hiufung V. Chu
DOI:10.1021/ol050361p
日期:2005.4.14
[reaction: see text] A high-yielding method is described for the rapid synthesis of very hindered cyclohexenes by the Diels-Alderreaction of hindered silyloxy dienes and dienophiles using the mixed Lewis acid catalyst system (AlBr(3)/AlMe(3)). Thus, reaction of the hindered diene 4 with various substituted enones gave good yields of the expected cycloadducts even though both partners are quite sterically
.beta.-Stannyl Allylic Alcohols through Photooxygenation (Schenck Reaction) of Vinylstannanes and Reduction of the Resulting Allylic Hydroperoxides: Synthesis and Selected Transformations
作者:Waldemar Adam、Peter Klug
DOI:10.1021/jo00089a010
日期:1994.5
beta-Stannyl allylic alcohols 2 were prepared regioselectively by photooxygenation (Schenck reaction) of the vinylstannanes 1 and subsequent;reduction of the resulting allylic hydroperoxides by sodium borohydride. This novel methodology makes the hitherto unknown oxyfunctionalized cyclic vinylstannanes conveniently accessible, which constitute valuable building blocks in organic synthesis. For example, palladium-catalyzed coupling of these vinylstannanes 2 with allylic and vinylic halides produced the P-substituted allylic alcohols 3 in good yields. Tin-lithium exchange directly on the oxyfunctionalized vinylstannanes 2 afforded the corresponding lithio dianions, which on reaction with aldehydes led to the allylic diols 4. Furthermore, iododestannylation of the beta-stannyl allylic alcohols 2 gave the respective vinyl iodides 5.
RITTER, KURT, TETRAHEDRON LETT., 31,(1990) N, C. 869-872