33674-46-3Relevant academic research and scientific papers
Catalytic asymmetric synthesis of epoxides from aldehydes using sulfur ylides with in situ generation of diazocompounds
Aggarwal, Varinder K.,Alonso, Emma,Hynd, George,Lydon, Kevin M.,Palmer, Matthew J.,Porcelloni, Marina,Studley, John R.
, p. 1430 - 1433 (2007/10/03)
A practical, general, and convergent to epoxides with control of the relative and absolute stereochemistry has been achieved by generating the reactive intermediate (the diazo compound) in situ from tosylhydrazone salts (see scheme, PTC = phase-transfer catalyst, Ts = toluene-4-sulfonyl). High yields (58-82%), high d.r. (88:12-98:2), and high ee values (87-94%) have been obtained using a new class of stable chiral sulfides at low catalyst loading (5 mol%) and [Rh2(OAc)4] (0.5 mol%).
Process for the preparation of an oxirane, azirdine or cyclopropane
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, (2008/06/13)
A process for the preparation of an oxirane, aziridine or cyclopropane of formula (I) wherein, X is oxygen, NR4 or CHR5 ; R1 is hydrogen, alkyl, aryl, heteroaromatic, heterocyclic or cycloalkyl; R2 is hydrogen, alkyl, aryl, heteroaromatic, CO2 R8, CHR14 NHR13, heterocyclic or cycloalkyl; or R1 and R2 join together to form a cycloalkyl ring; R3 is hydrogen, alkyl, aryl, heteroaromatic, CO2 R8, R83 Sn, CONR8 R9 or trimethylsilyl; R4 and R5 are, independently, alkyl, cycloalkyl, aryl, heteroaromatic, SO2 R8, SO3 R8, COR8, CO2 R8, CONR8 R9 or CN, or R4 can also be P(O)(aryl)2 ; R8 and R9 are independently alkyl, aryl or arylalkyl; R13 and R14 are independently hydrogen, alkyl or aryl; the process comprising reacting a mixture of a compound of formula (II), wherein R1, R2 and X are as defined above, and a sulphide of formula SR6 R7, wherein R6 and R7 are independently alkyl, aryl or heteroaomatic, or R6 and R7 join together to form a cycloalkyl ring which optionally includes an additional heteroatom, with either (i) a metallocarbon obtainable by reacting an alkylmetal with a methane derivative of formula CHR3 X'X", wherein R3 is as defined above, and X' and X" are independently, a leaving group, or (ii) a metallocarbon obtainable by reacting a compound of formula (III), (wherein R3 may not be hydrogen) with a suitable organometallic or inorganic reagent.
Proprietes nucleophiles des carbenoides monohalogenes non fonctionnels
Villieras, J.,Kirschleger, B.,Tarhouni, R.,Rambaud, M.
, p. 470 - 478 (2007/10/02)
The coupling of non functionalised monohalocarbenoids R1-CXLi-R2 1 (R1 = alkyl, H ; R2 = H, CH3) with carbonyl compounds at -115 degree leads to the formation of lithium salts of halohydrins which readily give epoxides (via lithium halide elimination) at -95 degree in the presence of lithium bromide.The regiospecific synthesis of α-haloketones and α-haloaldehydes can be achieved by acylation of 1 with esters.A total lack of reactivity of 1 towards powerful alkylating electrophiles has been observed showing that they are not nucleophilic organometallics.The reactivity with carbonyl compounds seems to be promoted by the carbonyl-lithium (from the carbenoid) complexation.A correlation between nucleophilic/electrophilic properties of carbenoids (mono-, di- and trihalo-) and their assigned structure (metallocarbenium halides) is discussed.
