114262-58-7Relevant academic research and scientific papers
Application of the lithiation-bborylation reaction to the preparation of enantioenriched allylic boron reagents and subsequent in situ conversion into 1,2,4-trisubstituted homoallylic alcohols with complete control over all elements of stereochemistry
Althaus, Martin,Mahmood, Adeem,Suarez, Jose Ramon,Thomas, Stephen P.,Aggarwal, Varinder K.
supporting information; experimental part, p. 4025 - 4028 (2010/05/14)
The reactions of Hoppe's lithiated carbamates with vinylboranes and boronic esters give allylic boranes/boronic esters, and subsequent addition of aldehydes provides a new route to enantioenriched homoallylic alcohols with high enantiomeric ratios and diastereomeric ratios. Specifically, reactions of sparteine-complexed lithiated carbamates with frans-alkenyl-9-BBN derivatives followed by addition of aldehydes gave (Z)-anti-homoallylic alcohols in greater than 95:5 er and 99:1 dr. However, in the special case of the methyl-substituted lithiated carbamate, diamine-free conditions were required to achieve high selectivity. Reactions of sparteine-complexed lithiated carbamates with (2)-alkenyl pinacol boronic esters and (E)-alkenyl neopentyl boronic esters gave (E)-syn- and (E)-anti-homoallylic alcohols, respectively, in greater than 96:4 er and 98:2 dr. In these reactions, a Lewis acid (MgBr2 or BF 3·OEt2) was required to promote both the 1,2-metalate rearrangement and the addition of the intermediate allylic boronic ester to the aldehyde. This methodology provides a general route to each of the three classes of homoallylic alcohols with high selectivity.
ON THE STEREOSELECTIVITY OF REACTIONS BETWEEN Α-METHYLBUT-2-ENYLSTANNANES AND ALDEHYDES.
Hull, Caroline,Mortlock, Simon V.,Thomas, Eric J.
, p. 1007 - 1016 (2007/10/02)
α-Methylbut-2-enylstannanes (7) - (9) react stereoselectively on heating with aldehydes to form anti-5-hydroxy-4-methyl-Z-pent-2-enes (16) and (17).In the presence of BF3*Et2O, the major products are the corresponding syn-5-hydroxy-4-methyl-E-pent-2-enes
Stereoselective Synthesis of Z-Alkenes from α-Methylcrotylstannanes and Aldehydes
Hull, Caroline,Mortlock, Simon V.,Thomas, Eric J.
, p. 5343 - 5346 (2007/10/02)
α-Methylcrotylstannanes (6)-(8) and aldehydes react stereoselectively on heating to give anti-5-hydroxy-4-methyl-Z-pent-2-enes (9) and (10).
