The optimization of the cross-coupling of alkynylglucopyranoses is reported in this communication.

(Final version not submitted in Time)

The metabotopic glutamate receptors (mGluRs) constitute a new family of excitatory amino acid receptors, which modulates the synaptic transmission by coupling to second messengers through G-proteins.[1] To date, mGluRs have been distinguished into three groups, based on sequence homology, signal transduction mechanisms and agents pharmacology. In particular, receptors of group III (mGluR4 and mGluR6-8) are characterized by their selective response to several phosphonic acid derivatives. Thus, they are selectively activated by L-2-amino-4- phosphonobutanoic acid (L-AP4, 1 in scheme 1) and competitively antagonized by the a-methylated derivatives of LAP4 (MAP4, 2) and 4-phosphonophenylglycine (MPPG, 3).[2]

a-Phoshono esters are widely employed substrates in olefin synthesis via Wadsworth-Emmons reaction.[1] Recently, Collignon and et al have described the organostannyl derivatives as useful intermediates in the synthesis of alkenylphosphonates.[2] In this communication we report our preliminary results on the stereoselective synthesis of amino acids containing alkenylphosphonates by using the a-triorganostannylated bislactim ether

Over the past decade, great progress has been made in the field of heterocyclic synthesis by the aza-Wittig methodology. The key intermediate iminophosphoranes can be prepared either by the Staudinger reaction from organic azides or by Kirsanov reaction from primary amines. Previously, we described an efficient synthesis for pyrimidothienopyridazines derivatives via intramolecular aza-Wittig reaction heterocyclization strategy.1 In this communication, we report the synthesis for pyridothienopyridazine and pyrimidothienopyridazine derivatives via aza-Wittig/electrocyclization and aza-Wittig/nucleophilic intramolecular hetero conjugate addition, respectively.

A catalytic amount of trimethylsilyl triflate (TMSOTf) remarkably facilitated the selective conjugate addition of a variety of silyl phosphites, prepared in situ from dialkyl phosphites and N,Obis( trimethysilyl)acetamide, to cyclic enones giving 1,4-adducts in high yields.

Syntheses of linearly fused ribbons of carbocyclic six-membered rings are accomplished by Diels-Alder cycloadditions of a diene (2,3-diheptylidene-1,2,3,4-tetrahydronaphthalene) and a bis-diene (2,3,6,7-tetraheptylidene-1,2,3,4,5,6,7,8-octahydroanthracene) to a bis-dienophile (1,4,5,8-anthradiquinone) and a dienophile (1,4-anthraquinone). The Diels-Alder adducts were dehydrogenated to several more highly unsaturated molecular ribbons.

Dianion of 2,3'-biquinolyl with aryl- and hetaryl halides forms product of arylation to 4'-position, which on treatment with alkyl halides or water yield 1'-alkyl-1',4'dihydro-2,3'-biquinolyls or 4'-aryl-1',4'-dihydro-2,3'-biquinolyls respectively. The oxydation of the latter leads to 4'-aryl-2,3'-biquinolyls. The cation dependence of the arylation is shown.

The enantioselective synthesis of alpha amino acids which contain an additional chiral center at a remote position presents an important and complex synthetic problem. We have previously described the employment of a hetero Diels-Alder reaction for this purpose.1 In this project this methodology was notably extended, as demonstrated by the short synthesis of (2R,5R)-2-amino-4-hydroxyhexanoic acid.

The synthesis of protected thiophospho amino acids, either as thiophosphotriesters or -diesters, conceived as building blocks for solid-phase synthesis of thiophosphorylated peptides is described. The thiophosphotriesters 4-9, namely O,O-diprotected, -thiophosphorylated N-Alloc, N-Fmoc and N-Boc protected serine, threonine and tyrosine, were prepared in a one-pot procedure from the corresponding N-protected amino acids. From O,O-dibenzyl N-Fmoc serine thiophosphate 7, either S-benzyl (10) or O-benzyl (11) thiophosphodiesters can be obtained.