hetero-Michael (DIHMA) reaction to alkynones was applied. The sequence allows for introduction of numerous substituents on the scaffold and for variation of stereochemistry. [5.5]-Spiroketals bearing an additional ketone were obtained in high overall yields. Further diversification was achieved by reduction of the ketone and reductive amination using polymer-supported borohydride, Grignard reaction and conversion
Enantioselective and Catalytic Method for α-Crotylation of Aldehydes with a Kinetic Self-Refinement of Stereochemistry
作者:Andrei V. Malkov、Mikhail A. Kabeshov、Maciej Barłog、Pavel Kočovský
DOI:10.1002/chem.200802224
日期:2009.2.2
Kinetic refinery: A practical, highly stereoselective, two‐step catalytic protocol for the α‐allylation of aldehydes, starting from crotyltrichlorosilanes, has been developed (see scheme). In each reaction step, one of the stereoisomers reacted faster than the other, which resulted in a kinetic stereochemical (E/Z) self‐refinement of the system and led to the formation of virtually enantiomerically
Palladium-Catalyzed Stereoselective Intramolecular Oxidative Amidation of Alkenes in the Synthesis of 1,3- and 1,4-Amino Alcohols and 1,3-Diamines
作者:Andrei V. Malkov、Darren S. Lee、Maciej Barłóg、Mark R. J. Elsegood、Pavel Kočovský
DOI:10.1002/chem.201400123
日期:2014.4.22
An efficient and practical Pd‐catalyzed intramolecular oxidative allylic amidation provides facile access to derivatives of 1,3‐ and 1,4‐aminoalcohols and 1,3‐diamines. The method operates under mild reaction conditions (RT) with molecular oxygen (1 atm) as the sole reoxidant of Pd. Excellent diastereoselectivities were attained with substrates bearing a secondary stereogenic center
The First Example of Enantioselective Allyl Transfer from a Linear Homoallylic Alcohol to an Aldehyde
作者:Teck-Peng Loh、Chi-Lik Ken Lee、Kui-Thong Tan
DOI:10.1021/ol0263999
日期:2002.8.1
see text] The first example of enantioselective linear homoallylic alcohol transfer reaction was revealed. In all cases, the whole rearrangement is thermodynamically favorable and a steric effect is the drivingforce of this reaction. The preservation of the stereocenter and olefin geometry together with the isolation of gamma-adduct homoallylic alcohols in one isomeric form have warranted the proposed
Highly (<i>E</i>)-Selective BF<sub>3</sub>·Et<sub>2</sub>O-Promoted Allylboration of Chiral Nonracemic α-Substituted Allylboronates and Analysis of the Origin of Stereocontrol
作者:Ming Chen、William R. Roush
DOI:10.1021/ol1007444
日期:2010.6.18
delta-Methyl-substituted homoallylic alcohols 2 were prepared in 71-88% yield, E:Z>30:1 and 93% to >95% ee via BF3 center dot Et2O-promoted allylboration with alpha-Me-allylboronate 1. The origin of high (E)-selectivity is proposed.