Hydroxy-directed regio-diastereoselective ene reaction of singlet oxygen with chiral allylic alcohols
作者:Waldemar Adam、Bernd Nestler
DOI:10.1021/ja00065a013
日期:1993.6
The photooxygenation of chiral allylic alcohols 1a, (Z)-1f-k, ethers 1b-d, and acetate 1e gave the corresponding hydroperoxy homoallylic alcohols and derivatives 2 through the enereaction with singletoxygen. While the reaction of the acetate 1e proceeded erythro-diastereoselectively as a result of the classical cis effect, for the allylic alcohols 1a and (Z)-1f-k, in which an alkyl group is located
手性烯丙醇 1a、(Z)-1f-k、醚 1b-d 和乙酸酯 1e 的光氧化反应通过与单线态氧的烯反应得到相应的氢过氧高烯丙醇和衍生物 2。由于经典的顺式效应,乙酸酯 1e 的反应以赤型非对映选择性进行,对于烯丙醇 1a 和 (Z)-1f-k,其中烷基位于带羟基的取代基的顺式,高观察到threo选择性。这一发现可以通过立体中心的亲核羟基官能团与进入的亲电子单线态氧亲烯体的配位来解释
Rh-Catalyzed Kinetic Resolution of Enynes and Highly Enantioselective Formation of 4-Alkenyl-2,3-disubstituted Tetrahydrofurans
作者:Aiwen Lei、Minsheng He、Xumu Zhang
DOI:10.1021/ja0351950
日期:2003.9.1
Rh-catalyzedcycloisomerization of enynes ether with a substituent at the allylic position was examined using (rac)-BINAP, and excellent selectivity was observed. When enantiomerically pure BINAP was used as the ligand, a process that combines kinetic resolution and diastereoselectivity together was developed, in which an enantiomeric product with multiple stereogenic centers was obtained in >99% ee
Stereo- and regioselectivity in iodo diol formation from acyclic allylic alcohols
作者:A. Richard Chamberlin、Robert L. Mulholland
DOI:10.1016/0040-4020(84)80012-5
日期:1984.1
with a variety of acyclicallylicalcohols was investigated. Both aqueous iodine and acetylhypoiodite convert certain alkenols into iododiols and acetoxy iodoalcohols, respectively, with regio- and stereoselectivities as high as 99%. Protection of the alcohol group lowers the selectivity only slightly. Structural factors that control the regioselectivity ofiodohydrin formation in these substrates
Diastereoselective Catalytic Epoxidation of Chiral Allylic Alcohols by the TS-1 and Ti-β Zeolites: Evidence for a Hydrogen-Bonded, Peroxy-Type Loaded Complex as Oxidizing Species
The similar diastereoselectivities as for peracids implicate a pentacoordinated metal peroxy species in the epoxidation of chiral allylic alcohols by the titanium-containing zeolites TS-1 and Ti-beta. In the loaded complex, the allylic alcohol substrate is fixed through hydrogen bonding to the metal center, with A(1,3) strain as the dominant conformational feature. By comparison of the diastereoselectivities to those for VO(acac)(2)/t-BuOOH, we exclude a peroxy-type complex with direct coordination of the allylic alcohol to the titanium center by means of metal-alcoholate bonding. Neither does a peroxo-type titanium complex apply, as confirmed by comparing the diastereoselectivities with those observed for dioxiranes. With the help of tert-butyl-substituted allylic alcohols as substrates, which are not epoxidized by the TS-1 but by the Ti-beta catalyst, it was unequivocally confirmed that the oxidation occurs inside of the zeolite and not on the outer surface.
Adam, Waldemar; Kumar, Rajiv; Reddy, T. Indrasena, Angewandte Chemie, 1996, vol. 108, # 8, p. 944 - 947
作者:Adam, Waldemar、Kumar, Rajiv、Reddy, T. Indrasena、Renz, Michael