Swern oxidation typical procedure

Procedure: 25 mL 1-neck flask, stirbar, septum, N2 inlet

Dissolved 0.077 mL of oxalylchloride (II) in 4.0 mL of dry CH2Cl2. Stirred; cooled to -78 C. Added 0.125 mL of DMSO. Stirred 10 min. Added a solution of 0.096 g of alcohol I in 1.0 mL of CH2Cl2. Stirred 15 min. Added 0.250 mL Et3N. After 15 min, warmed to 0 C. After 10 min TLC showed complete reaction. The reaction mixture was placed on a silica gel column and the product was isolated by flash chromatography .

notes

1. temp is critical for high yielding.
2. other than oxalylchloride, many activator can be used to overcome problem caused by oxalylchloride (ex. Cl-), ex. P2O5.


cited from
http://www.alsnotebook.com/oxidswern.html

an approach to Actinophyllic Acid

This synthesis plan was made by me about half a year before Overmann's beautiful synthesis of the same molecular.

An approach to Sordaricin

This proposal is just another application of carbene chemistry in the total synthesis of natural products.

The armed–disarmed concept

The armed–disarmed concept refers to the relative ease
or difficulty of activating a sugar as a glycosyl donor in
glycosylation reactions.1 Disarmed glycosyl donors have
highly electron withdrawing protecting groups (e.g., esters,
amides) that destabilize the formation of the oxycarbenium
ion/ion pair2 during the course of the glycosylation,
whereas less electron withdrawing protecting groups (e.g.,
ethers) are less destabilizing and therefore arm the glycosyl
donor.

Tetrahedron Letters 49 (2008) 2546–2551

preparation of [Me2SSMe+][BF4-] (DMTSF)

what DMTSF can do?
electrophilic sulfenylation reagent capable of reacting with nucleophilic atoms;² reacts with electron-rich alkenes to promote addition reactions,³ cyclizations;⁴ activates dithioacetals,⁵ trithioorthoesters,⁶ and thioglycosides⁷ for carbon–carbon or carbon–heteroatom bond forming reactions). from e-EROS Encyclopedia of Reagents for Organic Synthesis.

Inorganic Chemistry, Vol. 42, No. 8, 2003
Following the published procedure,
solution containing 0.74 mL of methyl disulfide (8.06 mmol) in
7 mL of CH3CN was added dropwise to an equimolar amount of
Me3O+BF4- (1.04 g, 8.06 mmol) dissolved in 8 mL of CH3CN
at 0 °C. After the mixture had been stirred for 2 h at 0 °C, dry
ether was added to precipitate dimethylthiomethylsulfonium fluoroborate
([Me2SSMe+][BF4-]) as a white solid that was stored in
the glovebox at -36 °C (1.1 g; yield, 69%).

An example of protection of alkene by Diels-alder rxn

New approaches for the synthesis of erythrinan alkaloids

Org. Biomol. Chem., 2009, 7, 1963–1979

retro d-a reaction happened by heating in vacuum. 80% yield.

A synthetic proposal of calicheamicinone

This synthetic plan features a rhodium mediated cyclopropanation and a curtius rearrangement. the overall steps is about 16 which is almost half of the existing synthesis!
The biggest problem I can forsee is the stability of the enediyne before the cyclopropanation.

keyword: calicheamicin, calicheamicinone, retrosynthetic plan, proposal, synthesis