90760-65-9Relevant academic research and scientific papers
A Catalytic Approach for Enantioselective Synthesis of Homoallylic Alcohols Bearing a Z-Alkenyl Chloride or Trifluoromethyl Group. A Concise and Protecting Group-Free Synthesis of Mycothiazole
Morrison, Ryan J.,Van Der Mei, Farid W.,Romiti, Filippo,Hoveyda, Amir H.
supporting information, p. 436 - 447 (2020/01/09)
A protecting group-free strategy is presented for diastereo- and enantioselective routes that can be used to prepare a wide variety of Z-homoallylic alcohols with significantly higher efficiency than is otherwise feasible. The approach entails the merger of several catalytic processes and is expected to facilitate the preparation of bioactive organic molecules. More specifically, Z-chloro-substituted allylic pinacolatoboronate is first obtained through stereoretentive cross-metathesis between Z-crotyl-B(pin) (pin = pinacolato) and Z-dichloroethene, both of which are commercially available. The organoboron compound may be used in the central transformation of the entire approach, an α- and enantioselective addition to an aldehyde, catalyzed by a proton-activated, chiral aminophenol-boryl catalyst. Catalytic cross-coupling can then furnish the desired Z-homoallylic alcohol in high enantiomeric purity. The olefin metathesis step can be carried out with substrates and a Mo-based complex that can be purchased. The aminophenol compound that is needed for the second catalytic step can be prepared in multigram quantities from inexpensive starting materials. A significant assortment of homoallylic alcohols bearing a Z-F3C-substituted alkene can also be prepared with similar high efficiency and regio-, diastereo-, and enantioselectivity. What is more, trisubstituted Z-alkenyl chloride moiety can be accessed with similar efficiency albeit with somewhat lower α-selectivity and enantioselectivity. The general utility of the approach is underscored by a succinct, protecting group-free, and enantioselective total synthesis of mycothiazole, a naturally occurring anticancer agent through a sequence that contains a longest linear sequence of nine steps (12 steps total), seven of which are catalytic, generating mycothiazole in 14.5% overall yield.
Srereoselective Synthesis of Alcohols, XXIII Transfer of Chirality on Addition of (α-Chloroallyl)boronates to Aldehydes
Hoffmann, Reinhard W.,Landmann, Bernd
, p. 2013 - 2024 (2007/10/02)
The preparation of the (α-chloroallyl)boronate 4 of 92percent e.e. is described.Its addition toachiral aldehydes resulted in the homoallyl alcohols 6 of 82-92percent e.e.Cooperative diastereoface selectivity on addition of ent-4 to isopropylideneglyceraldehyde (22) gave the product 23 of high diastereomeric purity.Reagent control of stereoselectivity on addition of 4 to 22 resulted in 25 in 77percent diastereomeric purity.
