Osmium Tetroxide-Promoted Catalytic Oxidative Cleavage of Olefins: An Organometallic Ozonolysis
作者:Benjamin R. Travis、Radha S. Narayan、Babak Borhan
DOI:10.1021/ja017295g
日期:2002.4.1
A mild, organometallic alternative to ozonolysis utilizing oxone and OsO(4) is presented. This is a direct oxidation of olefins via the carbon-carbon cleavage of an osmate ester by the action of oxone. Twenty-four different olefins were converted to their corresponding ketones or carboxylic acids in high yields (>80%). Free alcohols, acetate- and benzyl-protected alcohols, and 1,2-diols were stable
Highly efficient Rh(I)/tris-binaphthyl monophosphite catalysts for hydroformylation of sterically hindered alkyl olefins
作者:Gonçalo N. Costa、Rui M.B. Carrilho、Lucas D. Dias、Júlio C. Viana、Gilberto L.B. Aquino、Marta Pineiro、Mariette M. Pereira
DOI:10.1016/j.molcata.2016.02.016
日期:2016.5
Abstract The hydroformylation of highly substituted alkyl olefins was efficiently performed, with use of rhodium(I)/tris-binaphthyl monophosphite catalysts, containing different ether substituents at the 2′-binaphthyl position (OMe, OBn, OCHPh 2 and OAdamantyl). A systematic kinetic study, carried out for hydroformylation of methyl non-3-enoate, has shown a significant influence of the ligand’s OR group
Bioinspired-Metalloporphyrin Magnetic Nanocomposite as a Reusable Catalyst for Synthesis of Diastereomeric (−)-Isopulegol Epoxide: Anticancer Activity Against Human Osteosarcoma Cells (MG-63)
developed a green epoxidation approach for the synthesis of the diastereomers of (-)-isopulegol benzylether epoxide using molecular oxygen as the oxidant and a hybrid manganese(III)-porphyrin magnetic reusable nanocomposite as the catalyst. High activity, selectivity, and stability were obtained, with up to four recycling cycles without the loss of activity and selectivity for epoxide. The anticancer effect
Silylene-Mediated Ring Contraction of Homoallylic Ethers To Form Allylic Silanes
作者:Laura E. Bourque、Pamela A. Haile、K. A. Woerpel
DOI:10.1021/jo901111j
日期:2009.9.18
(−)-Isopulegol derivatives undergo a ring contraction under silylene-mediated conditions to provide cyclopentane products. Silylene transfer to other homoallylic ethers did not provide the ring contraction products. Allylic silane products were elaborated to determine the stereochemicalcourse of the ring contraction reaction. A mechanism for the transformation is proposed.
was subjected to hydroxylation and epoxidation, then aminolysis of the served oxiranes delivered aminodiols. On the other hand, (−)-isopulegol was oxidised to diol, which was again converted into both dibenzyl- and monobenzyl-protected diol derivatives. The products were transformed into aminoalcohols and aminodiols, respectively, by aminolysis of their epoxides. The ring opening of epoxides, derived
从市售的 (-)-isopulegol 开发了一个新的基于异胡薄荷醇的双功能和三功能手性配体家族。实现了伯胺对 (+)-α-亚甲基-γ-丁内酯的亲核加成,然后还原获得的 β-氨基内酯,在高度立体选择性反应中提供氨基二醇。(-)-异胡薄荷醇的环氧化和随后用伯胺开环的环氧乙烷产生N-取代的氨基二醇。还研究了这些氨基二醇与甲醛的区域选择性闭环。异胡薄荷醇的苄基化提供O-苄基保护的异胡薄荷醇,其通过以下途径转化为氨基醇相应环氧化物的环氧化和开环。首先对苄基保护的异胡薄荷醇进行羟基化和环氧化,然后对所提供的环氧乙烷进行氨解,从而产生氨基二醇。另一方面,(-)-异胡薄荷醇被氧化为二醇,其再次转化为二苄基和单苄基保护的二醇衍生物。通过环氧化物的氨解作用,产物分别转化为氨基醇和氨基二醇。衍生自二醇与伯胺的环氧化物的开环也用于产生氨基三醇。(-)-异胡薄荷醇或其衍生物与 OsO 4的二羟基化/NMO 得到基