143446-96-2Relevant academic research and scientific papers
Reaction of 1-Phenyl-3-borolenes with Aldehydes, Ketones, and Ketenes: Synthesis of 1,2-Oxaborolane Derivatives, 2,3-anti-1,3-Diols and Unsaturated β-Hydroxyalkyl Ketones
Herberich, Gerhard E.,Englert, Ulli,Wang, Shaotian
, p. 297 - 304 (2007/10/02)
1-Phenyl-3-borolenes (1a: R1 = H; b R1 = Me) react with aldehydes R2CHO to give cis-1,2-oxaborolanes (2, R2 = e.g.Me, Ph, CH=CH2, tBu, CCl3, R3 = H).Yields are nearly quantitative.Stereoselectivities usually are 100percent (but only 95percent for R2 = CH=CH2, 97percent for R2 = Me).Oxidation with NaOH/H2O2 in THF affords homoallylic anti-1,3-diols HOCR2R3-CR11(=CH2)>CH2OH (3).An X-ray diffraction analysis of 3a (R2 = p-tolyl) proves the assigned stereochemistries.Ketones R2R3CO react analogously.Ketenes R2CCO form 5-alkylidene-4-vinyl-1,2-oxaborolanes (4), which tend to undergo double-bond migration.Oxidation produces two types of β-hydroxyalkyl ketones R22CHCOCCH2OH (5) and R22CHCOCMeCH2OH (6).Key Words: Diastereoselective synthesis / Homoallylic alcohols / 1,3-Diols, homoallylic / β-Hydroxyalkyl ketones / 2,5-Dihydro-1H-boroles / 1,2-Oxaborolanes
