Functional groups toluenesulfonyl

A smdy of the substrate scope revealed that mono-, di-, and trisubstituted vinylcyclopropanes were aU suitable substrates to give cyclohexenones (resulting from cleavage of bond b ) as dominant products in moderate to good yields. The presence of a lot of functional groups such as TBS-protected hydroxyl, Ts- and Boc-protected amino, chloro, toluenesulfonyl, and cyano was well tolerated. It was noteworthy that the [5-1-1] carbonylation reaction could even be conducted catalytically. For example, 34a was produced in 73% yield from 33 in the presence of only 5 mol% Fe(CO)s (Scheme 17.8). 

The pyrrolidine derivative 314, a skeletal analog of the antitumor antibiotic anisomycin, was synthesized from the acetal derivative 16b. The 5-OH group of 16b was tosylated and then substituted with sodium azide. Reduction (sodium borohydride) of the lactone group afforded an open-chain derivative, which was selectively protected to give 313. Hydrogenation of the azide function, followed by p-toluenesulfonylation, led to 314 by an intramolecular nucleophilic displacement (284). 

Axenrod and co-workers reported a synthesis of TNAZ (18) starting from 3-amino-l,2-propanediol (28). Treatment of (28) with two equivalents of p-toluenesulfonyl chloride in the presence of pyridine yields the ditosylate (29), which on further protection as a TBS derivative, followed by treatment with lithium hydride in THF, induces ring closure to the azetidine (31) in excellent yield. Removal of the TBS protecting group from (31) with acetic acid at elevated temperature is followed by oxidation of the alcohol (32) to the ketone (33). Treatment of the ketone (33) with hydroxylamine hydrochloride in aqueous sodium acetate yields the oxime (34). The synthesis of TNAZ (18) is completed on treatment of the oxime (34) with pure nitric acid in methylene chloride, a reaction leading to oxidation-nitration of the oxime group to em-dinitro functionality and nitrolysis of the A-tosyl bond. This synthesis provides TNAZ in yields of 17-21 % over the seven steps. 

One of the key steps in building the fused ring involves the reaction of the activated acetoacetate methylene group in that compound with toluenesulfonyl azide to give the diazo intemediate (12-1). Treatment of that product with rhodium acetate leads to a loss of nitrogen with the consequent formation of carbene (12-2) this inserts into the adjacent amide N—H bond to form a five-membered ring and thus the carbapenem (12-3) [15]. The first step in the incorporation of the thioenol function consists in the conversion of the ketone to the enol phosphate derivative... 

Specialty Isocyanates. Specialty isocyanates are organic isocyanates having the isocyanate function attached to a carbonyl group or to elements other than carbon. /t-Toluenesulfonyl isocyanate is used as a drying agent for organic solvents. Arenesulfonyl diisocyanates, such as m-phenylenedisulfonyl diisocyanate, are used as monomers for base-soluble polymers. Arenesulfonyl monoisocyanates are used as intermediates for pharmaceuticals and herbicides. 

Some ortho-substituted aromatic sulfonyl azides, like o-toluenesulfonyl azide (93), on thermolysis are converted into the corresponding sultams (94) (Scheme 60). The reaction probably involves intramolecular C—H bond insertion by the reactive o-toluenesulfonyl nitrene intermediate. The azide (N3- group also functions as a pseudohalide consequently,... 

The replacement of a carboxylic acid group by nitrile functionality can also be used for the preparation of labeled compounds, and conditions for alkaline hydrolysis which did not lead to conjugation in skipped dienes like linoleic acid were developed by the Barton group. In this case, the free-radical chain sequence is straightforward, with the methanesulfonyl (or p-toluenesulfonyl) radical acting as the chain carrier [26], This methodology also represents an interesting way for the preparation of nitriles without the necessity for amide formation followed by dehydration. 

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