Catalytic amounts of CuI salts, CpTiCl3, and [CpFe(CO)2]2 are similarly effective. 2-Methylpropane, generated after quench of excess TIBA can be trapped, and excess dibromomethane can be recycled, which makes the method industrially applicable. Solvent-free DIBAH or TIBA reduction of unsaturatedcarbonylcompounds, followed by in situ TIBA cyclopropanation of the unsaturated aluminum alcoholates in
In tandem reactions, cyclopropylcarbinols are obtained from allyloxylithium or -magnesium intermediates, generated in situ by alkylation of conjugated aldehydes, ketones, and esters as well as from allyl carboxylates or vinyloxiranes. Using this methodology, numerous fragrance ingredients and their precursors were efficiently converted to the corresponding cyclopropylcarbinols.
[EN] CYCLOPROPANATION PROCESS<br/>[FR] PROCÉDÉ DE CYCLOPROPANATION
申请人:GIVAUDAN SA
公开号:WO2009023980A1
公开(公告)日:2009-02-26
A method for the preparation of cyclopropyl carbinols by cyclopropanation of unsaturated alcoholates, utilising a reagent system selected from (A) magnesium metal and dibromomethane, and (B) dibromomethane and a tertiary Grignard reagent, the reaction being carried out in the presence of an ether solvent. The process is useful, for example, for the preparation of ingredients for the flavour and fragrance industry.
[EN] CYCLOPROPANATION OF SUBSTITUTED ALKENES<br/>[FR] CYCLOPROPANATION D'ALCÈNES SUBSTITUÉS
申请人:INT FLAVORS & FRAGRANCES INC
公开号:WO2017024126A1
公开(公告)日:2017-02-09
Disclosed is a cyclopropanation process comprising the step of reacting an alkene compound having at least one carbon-carbon double bond with at least one dihaloalkane. The reaction is carried out in the presence of (i) particulate metal Zn, (ii) catalytically effective amount of particulate metal Cu or a salt thereof, (iii) at least one haloalkylsilane, and (iv) at least one solvent.
A method for the preparation of cyclopropyl carbinols by cyclopropanation of unsaturated alcoholates, utilising a reagent system selected from (A) magnesium metal and dibromomethane, and (B) dibromomethane and a tertiary Grignard reagent, the reaction being carried out in the presence of an ether solvent.
The process is useful, for example, for the preparation of ingredients for the flavour and fragrance industry.