19171-57-4Relevant articles and documents
Synthesis of glycosyl chlorides using catalytic Appel conditions
Pongener, Imlirenla,Nikitin, Kirill,McGarrigle, Eoghan M.
, p. 7531 - 7535 (2019)
The stereoselective synthesis of glycosyl chlorides using catalytic Appel conditions is described. Good yields of α-glycosyl chlorides were obtained using a range of glycosyl hemiacetals, oxalyl chloride and 5 mol% Ph3PO. For 2-deoxysugars treatment of the corresponding hemiacetals with oxalyl chloride without phosphine oxide catalyst also gave good yields of glycosyl chloride. The method is operationaly simple and the 5 mol% phosphine oxide by-product can be removed easily. Alternatively a one-pot, multi-catalyst glycosylation can be carried out to transform the glycosyl hemiacetal directly to a glycoside.
Direct evidence of a multicentre halogen bond: Unexpected contraction of the P-XXX-P fragment in triphenylphosphine dihalides
Nikitin, Kirill,Mueller-Bunz, Helge,Gilheany, Declan
, p. 1434 - 1436 (2013)
Triphenylhalophosphonium halides, Ph3PX2, form crystals comprising bridged linear cations [Ph3P-X-X-X-PPh 3]+ where the X3 bridge is shortened from 6.56 A in Cl-Cl-Cl to 6.37 A in the Br-Br-Br system. It is proposed that this structure is stabilised by five-centre/six-electron (5c-6e) hypervalent interactions.
A Mild One-Pot Reduction of Phosphine(V) Oxides Affording Phosphines(III) and Their Metal Catalysts
Kapu?niak, ?ukasz,Plessow, Philipp N.,Trzybiński, Damian,Wo?niak, Krzysztof,Hofmann, Peter,Jolly, Phillip Iain
supporting information, p. 693 - 701 (2021/04/06)
The metal-free reduction of a range of phosphine(V) oxides employing oxalyl chloride as an activating agent and hexachlorodisilane as reducing reagent has been achieved under mild reaction conditions. The method was successfully applied to the reduction of industrial waste byproduct triphenylphosphine(V) oxide, closing the phosphorus cycle to cleanly regenerate triphenylphosphine(III). Mechanistic studies and quantum chemical calculations support the attack of the dissociated chloride anion of intermediated phosphonium salt at the silicon of the disilane as the rate-limiting step for deprotection. The exquisite purity of the resultant phosphine(III) ligands after the simple removal of volatiles under reduced pressure circumvents laborious purification prior to metalation and has permitted the facile formation of important transition metal catalysts.
Hypervalent Iodine-Based Activation of Triphenylphosphine for the Functionalization of Alcohols
Eljo, Jasmin,Carle, Myriam S.,Murphy, Graham K.
, p. 2871 - 2875 (2017/10/06)
The use of hypervalent iodine reagents as a general tool for the activation of PPh 3 and its application to the functionalization of alcohols is reported. Combination of PPh 3 with PhICl 2 or TolIF 2 gives dihalophosphoranes that are characterized by 31 P NMR, however, with PhIOAc 2, PhI(OTFA) 2, or the cyclic chloro(benzoyloxy)iodane, no phosphoranes were observed. Reaction of these iodanes with PPh 3 in the presence of primary, secondary, or tertiary alcohols results in either halogenation or acyl-transfer products in moderate to high yield.
