Highly diastereoselective hydrosilylations of allylic alcohols
作者:Mark G. McLaughlin、Matthew J. Cook
DOI:10.1039/c4cc00138a
日期:——
The highly syn-selective hydrosilylation of allylic alcohols was developed which, following oxidation, provided 1,3 alcohols containing two contiguous stereocentres.
Stereocontrol in intramolecular hydrosilylation of allyl and homoallyl alcohols: a new approach to the stereoselective synthesis of 1,3-diol skeletons
作者:Kohei. Tamao、Takashi. Nakajima、Ritsuo. Sumiya、Hitoshi. Arai、Noriko. Higuchi、Yoshihiko. Ito
DOI:10.1021/ja00279a097
日期:1986.9
31.30; H, 5.22; N, 36.52. Found: C, 31.34; H, 5.25; N, 36.70. Low-resolution mass spectral analysis showed the expected molecular ion at m / e 345. The infrared spectrum contained a cyano stretching peak at 2180 cm-'. The 31P NMR spectrum consisted of a singlet at -7.8 ppm. Crystals suitable for X-ray analysis were grown by slow evaporation of a solution of 2 in hexane. The structure of 2 is illustrated
Stereochemistry in the hydroboration of allylsilanes
作者:Ian Fleming、Nicholas J Lawrence
DOI:10.1016/s0040-4039(00)87839-9
日期:——
The hydroboration of allylsilanes is highly stereoselective in the sense (3 → 4 and 6 → 7), especially with 9-BBN as the hydroborating reagent. The products can be converted stereospecifically into 1,3-diol derivatives (5 and 8).
Rhodium(I)-catalyzed hydroboration of olefins. The documentation of regio- and stereochemical control in cyclic and acyclic systems
作者:David A. Evans、Gregory C. Fu、Amir H. Hoveyda
DOI:10.1021/ja00228a068
日期:1988.9
Catalyse par les complexes Rh(PPh 3 ) 3 Cl et [Rh(nbd)(diphos-4)]BF 4 (nbd=norbornadiene, diphos-4=bis-diphenylphosphino-1,4 butane)
催化复合物 Rh(PPh 3 ) 3 Cl et [Rh(nbd)(diphos-4)]BF 4 (nbd=降冰片二烯,diphos-4=双-二苯基膦基-1,4丁烷)
Substrate-controlled diastereoselectivities in catalyzed and uncatalyzed hydroborations of acyclic allylic alcohol derivatives: secondary orbital effects involving d.pi.-p.pi. interactions
作者:Kevin Burgess、Juanita Cassidy、Michael J. Ohlmeyer
DOI:10.1021/jo00003a023
日期:1991.2
Rhodium-mediated hydroborations of allylic alcohol derivatives 1-9 followed by oxidation give predominantly syn-2-methyl 1,3-diols whereas conventional hydroborations of the same substrates afford mostly anti products. It is proposed that mixing of delta*-orbitals involved in bonding at the asymmetric center with pi*-orbitals of the alkene lowers the LUMO involved in complexation of rhodium, and this could control diastereofacial selectivities in catalyzed hydroborations. Steric effects in catalyzed hydroborations are also discussed. The resulting hypotheses are tested with respect to catalyzed and uncatalyzed hydroborations of phenyl-substituted allylic alcohol derivatives 17-19 and Ph(C6F5)CHCM(e) = CH2 (21) (a model substrate with aromatic groups of a similar size but different electronic properties attached to the chiral center). All experimental observations described here for catalyzed hydroborations of chiral alkenes are consistent with the proposals outlined above.