433924-37-9Relevant academic research and scientific papers
Practical and Broadly Applicable Catalytic Enantioselective Additions of Allyl-B(pin) Compounds to Ketones and α-Ketoesters
Robbins, Daniel W.,Lee, KyungA,Silverio, Daniel L.,Volkov, Alexey,Torker, Sebastian,Hoveyda, Amir H.
supporting information, p. 9610 - 9614 (2016/08/10)
A set of broadly applicable methods for efficient catalytic additions of easy-to-handle allyl-B(pin) (pin=pinacolato) compounds to ketones and acyclic α-ketoesters was developed. Accordingly, a large array of tertiary alcohols can be obtained in 60 to >98 % yield and up to 99:1 enantiomeric ratio. At the heart of this development is rational alteration of the structures of the small-molecule aminophenol-based catalysts. Notably, with ketones, increasing the size of a catalyst moiety (tBu to SiPh3) results in much higher enantioselectivity. With α-ketoesters, on the other hand, not only does the opposite hold true, since Me substitution leads to substantially higher enantioselectivity, but the sense of the selectivity is reversed as well.
Stereoselective and competitive [1,2]- and [2,3]-wittig rearrangements of allyl heteroarylalkyl ethers
Capriati, Vito,Florio, Saverio,Ingrosso, Giovanni,Granito, Catia,Troisi, Luigino
, p. 478 - 484 (2007/10/03)
Several allyl heteroarylalkyl ethers have been synthesized and then deprotonated with nBuLi in THF at -78°C to give lithium derivatives. The lithium-bearing terminus was either the α- or the α′-carbon atom, depending on the associated proton acidity. In the absence of an external electrophile, a sigmatropic rearrangement occurs, generating a new C-C bond. Heteroarylalkyl homoallylic alcohols and allyl heteroarylalkylic alcohols were obtained as products of stereoselective [2,3]- or [1,2]-Wittig rearrangements, respectively. Homoallylic alcohols were obtained in high yields and with fairly good enantiomeric enrichments when the reactions were carried out in toluene with (-)-sparteine as the external chiral ligand.
