1250351-20-2Relevant academic research and scientific papers
The first direct and enantioselective cross-aldol reaction of aldehydes
Northrup, Alan B.,MacMillan, David W. C.
, p. 6798 - 6799 (2002)
The first enantioselective catalytic direct cross-aldol reaction that employs nonequivalent aldehydes has been accomplished using proline as the reaction catalyst. Structural variation in both the aldol donor (R1 = Me, n-Bu, Bn, 91 to >99%) and aldol acceptor (R2 = I-Pr, I-Bu, c-C6H11, Et, Ph, 97-99% ee) are possible while maintaining high reaction efficiency (75-88% yield). Significantly, this new aldol variant allows facile enantioselective access to a broad range of β-hydroxy aldehydes which are valuable intermediates in polyketide syntheses. Copyright
Asymmetric aldol reactions. A new camphor-derived chiral auxiliary giving highly stereoselective aldol reactions of both lithium and titanium(IV) enolates
Bonner, Mary Pat,Thornton, Edward R.
, p. 1299 - 1308 (2007/10/02)
A new, conformationally rigid camphor-derived N-propionyloxazolidinone effects asymmetric stereochemical control in syn-selective aldol condensations of the derived lithium and titanium(IV) enolates with a variety of aldehydes. Simple and diastereofacial selectivities of the reaction are high, and diastereomeric purities of the crude aldol adducts can be improved, usually by a single recrystallization, to levels of 98-99% in most cases. The observed facial selectivity is best explained by a transition structure in which intramolecular chelation between the oxazolidinone carbonyl oxygen and the metal induces an enolate π-facial differentiation; the major products observed are those expected from chelation control. Hydrolysis of the exocyclic carbonyl of the aldol adducts led to β-hydroxy-α-methylcarboxylic acids, with recovery of the chiral auxiliary. Consonant double-asymmetric induction with (R)-2-(benzyloxy)propanal gave the product expected from oxazolidinone chelation but nonchelation of the aldehyde benzyloxy group.
A NEW SYNTHESIS OF SUBSTITUTED SPIRO BUTYROLACTONES VIA DYOTROPIC REARRANGEMENT
Black, T.Howard,DuBay III, William J.
, p. 4787 - 4788 (2007/10/02)
Spiro butyrolactones bearing various α-substituents have been synthesized in three steps from acetic acid derivatives; the sequence employs a dyotropic rearrangement as its pivotal step.
