112383-48-9

Upstream product

• 74-88-4 methyl iodide 
• 17689-03-1 1-hexynyllithium 
• 286-20-4 cyclohexene oxide 
• 693-02-7 hex-1-yne 
• 286-20-4 cyclohexane-1,2-epoxide 
• 628-92-2 Cycloheptene 
• 53185-69-6 pimelaldehyde 
• 21406-61-1 pentyltriphenylphosphonium bromide 

Downstream Products

• 135924-85-5 C₁₂H₂₀O 

Relevant academic research and scientific papers

A study of the stereochemical features of 5-endo-trig iodocyclisations of 2-alkenyIcycloalkan-1-ols

Overall 5-endo-trig iodocyclisations of all isomers of the 2-alkenyIcyclopentan-l-ols and -cyclohexan-1-ols 11,12,14 and 16 have been examined. Only in the cases of the trans-alkenylcyclopentanols lia and 12a are the reactions either unsuccessful or low y

Two Enabling Strategies for the Stereoselective Conversion of Internal Alkynes into Trisubstituted Alkenes

An expedient method for the C-methylation of alkenylstannanes with formation of trisubstituted alkenes is described, which relies on the use of MeI in combination with copper thiophene-2-carboxylate (CuTC) as promotor and tetra-n-butylammonium diphenylphosphinate as an effective tin scavenger; in some cases, it proved beneficial to further supplement the mixture with catalytic amounts of Pd(PPh3)4. Under these conditions, the reaction is robust, high yielding, and compatible with many functional groups that might not subsist under more traditional conditions used to C-alkylate organotin derivatives. A qualitative analysis of the reaction profile suggested that the in situ formation of a reactive organocopper intermediate and its interception by MeI is only barely faster than O-methylation of the phosphinate additive by the same alkylating agent. To guarantee high yields and prevent net protodestannation from occurring, the reaction protocol had to be optimized such that these competing processes are properly decoupled. The new method is particularly well suited for the stereoselective preparation of the (E)-2-methylbut-2-en-1-ol motif that is present in numerous natural products. Alternatively, this particular target structure can be accessed starting from α-hydroxy alkenylsiloxane precursors, which get C-methylated upon exposure to CuI/LiOtBu and MeI by what is thought to be a Brook rearrangement/ alkylation sequence. The required substrates are best prepared by ruthenium-catalyzed trans-hydrosilylation or trans-hydrostannation of propargyl alcohols.

Enantioselective total synthesis and confirmation of the absolute and relative stereochemistry of streptorubin B

The enantioselective total synthesis of the pyrrolophane natural product streptorubin B is described. Key steps in the concise route include the application of a one-pot enantioselective aldol cyclization/Wittig reaction and an anionic oxy-Cope rearrangement to forge the crucial 10-membered ring. Comparisons between CD spectra of synthetic and natural samples of streptorubin B coupled with X-ray crystallography allowed for the determination of the absolute stereochemistry of this natural product for the first time. These studies also provided unambiguous proof of the relative configuration between the butyl side chain and the bispyrrole subunit. Additional studies revealed a novel atropstereoselective Paal-Knorr pyrrole condensation and provided fundamental experimental insight into the barrier for atropisomerization of the natural product.

Auxiliary-directed peroxidation of 1,4-dienes

The addition of singlet oxygen (1O2) to the proximal alkene of auxiliary-tethered 1,4-dienes and the addition of triplet oxygen 3O2) to the proximal position of the corresponding pentadienyl radicals both produce conjugated diene hydroperoxides in moderate to high diastereomeric excess. Negligible stereoselection is observed for additions of 1O2 to the distal alkene of Z,Z-heptadienes due to the lack of control of alkene conformation. Despite evidence for the intermediacy of highly constrained pentadienyl radicals, poor diastereoselection is also observed for distal addition of 3O2. The extent of olefin isomerization observed during radical oxygenations can be correlated with steric constraints on the intermediate pentadienyl and peroxyl radicals and may be relevant to literature reports of olefin isomerization during enzymatic oxygenations of unnatural fatty acids.

A Stereoselective Approach to Annulated Tetrahydrofurans by Iodocyclisations of 2-Alkenylcycloalkan-1-ols

Highly stereoselective iodocyclisations of the 2-alkenylcycloalkan-1-ols 7, 8, 10 and 11 under strictly anhydrous conditions give good to excellent yields of the annulated β-iodotetrahydrofurans 12-16.

BORON FLUORIDE PROMOTED OPENING OF EPOXIDES BY ORGANOCOPPER AND CUPRATE REAGENTS

In the presence of BF3 the reaction rate of organocopper and cuprate reagents with poorly reactive epoxides is dramatically enhanced.Lithium organocuprates are the best choice among the various organocopper and cuprate reagents tested.Even the dimesityl cyanocuprate is able to react with cyclohexene oxide in excellent yield.No products of cationic rearrangements are observed.The reaction with various epoxides shows a complete stereochemical (pure anti opening) and regiochemical control (attack on the less hindered side of the epoxide).