The Cleavage Reaction of 1,3-Diols. III. The Synthesis of a Pair of Diastereomeric Ditertiary 1,3-Diols and an Effect of Configuration on Mode of Cleavage1
Irreversible aldolization of ketones with bisdicyclohexylboron enediolates
作者:P. Veeraraghavan Ramachandran、Barnabas Otoo
DOI:10.1016/j.tetlet.2019.151102
日期:2019.10
Unlike the reported reversible addition of ketone enolborinates to ketones, the aldolization of ketones with bisboron enediolates derived from carboxylic acids proceeds without difficulty. A variety of α,β,β-trisubstituted-β-hydroxy acids have been thus synthesized in good to excellent yields and diastereoselectivities.
A case of highly diastereoselective addition to unsymmetrical ketones:lk-addition of (2-alkenyl)triphenoxytitanium derivatives
作者:Dieter Seebach、Leo Widler
DOI:10.1002/hlca.19820650704
日期:1982.11.3
(2-Butenyl)-, (4-methyl-2-pentenyl)-, and (2-heptenyl)triphenoxytitanium (2a–c) add to dialkyl, alkyl aryl-, and alkinyl aryl ketones to give high yields of tertiary homoallylic alcohols (5–12), which are diastereomerically enriched up to 98%. Configurational assignment by degradation of two of the products to olefins 15 and 18 - through β-hydroxy acids 13 and 16 and β-lactones 14 and 17 - leads to