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Articles Archive for August 2007

Still In The RBF »

[27 Aug 2007 | 26 Comments | 7,445 views]

Trost and Weiss. ACIEE, 2007, EarlyView. DOI: 10.1002/anie.200702637.
I wasn’t sure about this paper when I started reading it – the introduction, in which the ketone and acetylene functional groups are compared and contrasted, seemed quite out-of-place. Surely most readers are well aware of the utility of the alkyene group, and of the transformations which may be be performed on it. Hmm. Anyway, Trost’s route to this natural product is really quite nice, and, as the paper points out quite feverently, is reliant on some smart alkynylation chemistry.

As can be seen …

Still In The RBF »

[23 Aug 2007 | 25 Comments | 10,021 views]

Stoltz, Liu and Ferreira. JOC, 2007, ASAP. DOI: 10.1021/jo0710883.
An awesome read, this paper is a smart bit of work by the Stoltz group, looking at the synthesis of two members of the Cephalotaxus alkaloid family. They state that the members accessed in this route are biologically inactive, but point out that other members of the family are a bit more pokey (and can presumably be constructed using similar means.
The synthesis begins with one of my favourite reactions, a Johnson-Claisen rearrangement. This uses triethyl ortho acetate (which smells like …

Still In The RBF »

[17 Aug 2007 | 33 Comments | 8,876 views]

Pagenkopf and Wang. Org. Lett., 2007, ASAP. DOI: 10.1021/ol701797e.
Just a quick Org. Lett. to get back in the saddle, so to speak. The target is certainly appealing; quite an interesting array of functionality there. It does have some biological activity, as a Na/K ATPase inhibitor, but isn’t particularly potent. The chemistry gets interesting with a desymmeterisation of a diol using an orthoester to provide the acetate. Then they form the first THF using a tasty Mukaiyama cobalt-catalyzed aerobic oxidative cyclisation, a method popular with the group. They state …

Still In The RBF »

[6 Aug 2007 | 48 Comments | 10,419 views]

Deprés and Carret. ACIEE, 2007, EarlyView. DOI: 10.1002/anie.200702031.
Isolated from the plant colloquially known as the “vomiting bush”, Geigerin is a member of the guaianolide family, represented in the 5,7,5 tricyclic structure. No further mention of the biological activity is noted in this paper, but they do point out that this isn’t the first synthesis of this family, referencing Lee and Bartons works.
The synthesis starts with a bit of chemistry quite familiar to the group, doing a regioselective [2+2] cycloaddition with diphosgene 2,2,2-trichloroacetyl chloride and 7-methylcycloheptatriene. In their previous papers, they …

Still In The RBF »

[1 Aug 2007 | 23 Comments | 9,476 views]

Ley, Veitch, Beckmann, Burke, Boyer and Maslen. ACIEE, 2007, Early View. DOIs: 10.1002/anie.200703027, 10.1002/anie.200703028.
In this part of the discussion, I’m going to cover the synthesis of the more complex fragment from the retrosynthesis given in the previous post, that of the decalin fragment. The subunit is certainly a challenge all by itself, containing ten contiguous stereocenters, and complex oxygenation. Most of the work on this fragment was referenced back to previous papers by the group, and from what I read, most of the information is in this Perkin 1, and …