179690-97-2Relevant academic research and scientific papers
One and Two-Carbon Homologation of Primary and Secondary Alcohols to Corresponding Carboxylic Esters Using β-Carbonyl BT Sulfones as a Common Intermediate
Bon, David J.-Y. D.,Ková?, Ond?ej,Ferugová, Vendula,Zále?ák, Franti?ek,Pospí?il, Ji?í
, p. 4990 - 5001 (2018/05/17)
Herein we report the efficient one- and two-carbon homologation of 1° and 2° alcohols to their corresponding homologated esters via the Mitsunobu reaction using β-carbonyl benzothiazole (BT) sulfone intermediates. The one-carbon homologation approach uses standard Mitsunobu C-S bond formation, oxidation and subsequent alkylation, while the two-carbon homologation uses a less common C-C bond forming Mitsunobu reaction. In this latter case, the use of β-BT sulfone bearing esters lowers the pKa sufficiently enough for the substrate to be used as a carbon-based nucleophile and deliver the homologated β-BT sulfone ester, and this superfluous sulfone group can then be cleaved. In this paper we describe several methods for the effective desulfonylation of BT sulfones and have developed methodology for one-pot alkylation-desulfonylation sequences. As such, overall, a one-carbon homologation sequence can be achieved in a two-pot (four step) procedure and the two-carbon homologation in a two-pot (three step) procedure (three-pot; four step when C-acid synthesis is included). This methodology has been applied to a wide variety of functionality (esters, silyl ethers, benzyls, heteroaryls, ketones, olefins and alkynes) and are all tolerated well providing good to very good overall yields. The power of our method was demonstrated in site-selective ingenol C20 allylic alcohol two-carbon homologation.
Intramolecular electron transfer initiated cation and radical formation through carbon-carbon bond activation
Wangyang, Tu,Floreancig, Paul E.
, p. 2389 - 2392 (2008/02/05)
Radical cations can be formed in a spatially and temporally controlled manner by appending a sacrificial photooxidant to an easily oxidized substrate, leading to intramolecular electron transfer upon irradiation. The anthraquinone carboxyl group is an effective photooxidant that can promote single electron oxidation from an appended arene. The resulting intermediates undergo a cleavage reaction through carbon-carbon bond activation to provide either cations or radicals that react to form a range of products.
Radical cyanocarbonylation using alkyl allyl sulfone precursors
Kim, Sangmo,Cho, Chang Ho,Kim, Sunggak,Uenoyama, Yoshitaka,Ryu, Ilhyong
, p. 3160 - 3162 (2007/10/03)
Acyl cyanides have been prepared by the three-component coupling reactions comprised of alkyl allyl sulfones, carbon monoxide, and p-tolylsulfonyl cyanide under tin-free radical reaction conditions. Georg Thieme Verlag Stuttgart.
Polycyclic molecules from linear precursors: Stereoselective synthesis of clavolonine and related complex structures
Evans, David A.,Scheerer, Jonathan R.
, p. 6038 - 6042 (2007/10/03)
(Chemical Equation Presented) A clever way to clavolonine: The total synthesis of the lycopodium alkaloid clavolonine (2) from a linear precursor 1 that contains the complete 16-carbon-atom chain is reported (see scheme). Intramolecular and transannular c
Synthetic study on naturally occurring acetylenic spiroacetal enol ethers: The first access to optically active 3,4-diacetoxy-2-formylmethylene- 1,6-dioxaspiro[4.5]decanes
Toshima, Hiroaki,Aramaki, Hisateru,Ichihara, Akitami
, p. 3587 - 3590 (2007/10/03)
Optically active 3,4-diacetoxy-2-formylmethylene-1,6- dioxaspiro[4.5]decanes have been synthesized from an acyclic keto-alcohol possessing an unsaturated aldehyde part via intramolecular conjugate addition. The C3- and C4-stereogenic centers were introduced via Sharpless asymmetric dihydroxylation of an acyclic conjugated ketone with modified AD- mix-α in high enantioselectivity (96% e.e.). This is the first access to optically active spiroacetal 2-enol ethers.
