17343-88-3Relevant articles and documents
Manganese dioxide can oxidise unactivated alcohols under in situ oxidation-Wittig conditions
Blackburn, Leonie,Wei, Xudong,Taylor, Richard J. K.
, p. 1337 - 1338 (1999)
The in situ alcohol oxidation-Wittig reaction using manganese dioxide as the oxidant has been applied to semi-activated and, for the first time, unactivated alcohols to furnish the corresponding α,β-unsaturated esters.
Synthesis of unsaturated esters from aldehydes: An inexpensive, practical alternative to the Horner-Emmons reaction under neutral conditions
Ledford, Brian E.,Carreira, Erick M.
, p. 8125 - 8128 (1997)
A practical, efficient, and mild process is described for the synthesis of unsaturated esters from aldehydes in good yields and diastereoselectivities. All of the reagents used in the protocol are commercially available at a nominal price: N2CHCO2Et, catalytic (1 mol%) ReOCl3(PPh3)2, and (EtO)3P. Additionally, the reaction process can be carried out successfully in good yields (85%) and diastereoselectivities (>20:1) with reagent-grade solvent without prior purification of the reagents.
Synthesis of Enantioenriched 3,4-Disubstituted Chromans through Lewis Base Catalyzed Carbosulfenylation
Denmark, Scott E.,Laverny, Aragorn,Menard, Travis
, p. 14290 - 14310 (2021/11/12)
A method for the catalytic, enantioselective, carbosulfenylation of alkenes to construct 3,4-disubstituted chromans is described. Alkene activation proceeds through the intermediacy of enantioenriched, configurationally stable thiiranium ions generated from catalytic, Lewis base activation of an electrophilic sulfenylating agent. The transformation affords difficult-to-generate, enantioenriched, 3,4-disubstituted chromans in moderate to high yields and excellent enantioselectivities. A variety of substituents are compatible including electronically diverse functional groups as well as several functional handles such as aryl halides, esters, anilines, and phenols. The resulting thioether moiety is amenable to a number of functional group manipulations and transformations. Notably, the pendant sulfide was successfully cleaved to furnish a free thiol which readily provides access to most sulfur-containing functional groups which are present in natural products and pharmaceuticals.
A One-Pot Synthesis of α,β-Unsaturated Esters From Esters
Hong, Chang Whee,Lee, Yong Jin,An, Duk Keun
, p. 1121 - 1125 (2021/06/01)
A convenient method for reductive Horner–Wadsworth–Emmons (HWE) olefination is described. The E-selective HWE homologation of various esters to α,β-unsaturated esters was readily achieved and gave the desired products in good-to-moderate yields under mild conditions. The one-pot reaction proceeds through an in situ generated aldehyde, formed via the partial reduction of an ester with lithium diisobutyl-t-butoxyaluminum hydride. The formation of cyclized metal acetal and subsequent decompose to the aldehyde for the olefination was found to be a crucial step in this C2-carbon homologation protocol.
Copper-Catalyzed Azide–Ynamide Cyclization to Generate α-Imino Copper Carbenes: Divergent and Enantioselective Access to Polycyclic N-Heterocycles
Chen, Yang-Bo,Deng, Chao,Liu, Rai-Shung,Liu, Xin,Luo, Chen,Wang, Ze-Shu,Ye, Long-Wu,Zhai, Tong-Yi,Zhang, Yi-Ping
supporting information, p. 17984 - 17990 (2020/08/21)
Here an efficient copper-catalyzed cascade cyclization of azide-ynamides via α-imino copper carbene intermediates is reported, representing the first generation of α-imino copper carbenes from alkynes. This protocol enables the practical and divergent synthesis of an array of polycyclic N-heterocycles in generally good to excellent yields with broad substrate scope and excellent diastereoselectivities. Moreover, an asymmetric azide–ynamide cyclization has been achieved with high enantioselectivities (up to 98:2 e.r.) by employing BOX-Cu complexes as chiral catalysts. Thus, this protocol constitutes the first example of an asymmetric azide–alkyne cyclization. The proposed mechanistic rationale for this cascade cyclization is further supported by theoretical calculations.
