Hybrid macrocycle formation and spiro annulation on cis-syn-cis-tricyclo[6.3.0.0^2,6]undeca-3,11-dione and its congeners via ring-closing metathesis

• Sambasivarao Kotha,
• Ajay Kumar Chinnam and
• Rashid Ali

Beilstein J. Org. Chem. 2015, 11, 1123–1128, doi:10.3762/bjoc.11.126

• as useful building blocks (Figure 2). The selection of these diones is based on their easy accessibility and also the symmetry involved with them. For example, with diones 1 and 2 one can apply a two-directional synthesis [53] to increase the brevity [54] of the overall synthesis. Earlier, we have

Two-directional synthesis as a tool for diversity-oriented synthesis: Synthesis of alkaloid scaffolds

• Kieron M. G. O’Connell,
• Monica Díaz-Gavilán,
• Warren R. J. D. Galloway and
• David R. Spring

Beilstein J. Org. Chem. 2012, 8, 850–860, doi:10.3762/bjoc.8.95

• Kieron M. G. O'Connell Monica Diaz-Gavilan Warren R. J. D. Galloway David R. Spring Department of Chemistry, University of Cambridge, Lensfield Rd, Cambridge, CB2 1EW, UK 10.3762/bjoc.8.95 Abstract Two-directional synthesis represents an ideal strategy for the rapid elaboration of simple starting

• materials and their subsequent transformation into complex molecular architectures. As such, it is becoming recognised as an enabling technology for diversity-oriented synthesis. Herein, we provide a thorough account of our work combining two-directional synthesis with diversity-oriented synthesis, with

• particular reference to the synthesis of polycyclic alkaloid scaffolds. Keywords: alkaloids; cascade reactions; chemical diversity; diversity-oriented synthesis; Lewis acid catalysis; two-directional synthesis; Introduction Diversity-oriented synthesis (DOS) aims to prepare structurally diverse compound

Recent advances in carbocupration of α-heterosubstituted alkynes

• Ahmad Basheer and
• Ilan Marek

Beilstein J. Org. Chem. 2010, 6, No. 77, doi:10.3762/bjoc.6.77

• was employed in the two-directional synthesis of the F-J fragment of Gambieric Acid [17]. On the other hand, when substituted ynol ether 7 (R and R1 = alkyl) was treated with the same organocopper reagents under the same conditions, the two substituents flanking the triple bond have opposite effects

Combining two-directional synthesis and tandem reactions, part 11: second generation syntheses of (±)-hippodamine and (±)-epi-hippodamine

• Annabella F. Newton,
• Martin Rejzek,
• Marie-Lyne Alcaraz and
• Robert A. Stockman

Beilstein J. Org. Chem. 2008, 4, No. 4, doi:10.1186/1860-5397-4-4

• axial C-5 methyl group. Both hippodamine (1) [5][6][7] and epi-hippodamine (2) [8] have been synthesized previously, and we reported syntheses of these two compounds using a two-directional synthesis / tandem, reaction approach in 2005 [9]. Scheme 1 details the key aspects to our earlier work [10

Methods for the synthesis of polyhydroxylated piperidines by diastereoselective dihydroxylation: Exploitation in the two-directional synthesis of aza-C-linked disaccharide derivatives

• Andrew Kennedy,
• Adam Nelson and
• Alexis Perry

Beilstein J. Org. Chem. 2005, 1, No. 2, doi:10.1186/1860-5397-1-2

• exploited in the two-directional synthesis of aza-C-linked disaccharide analogues. A two-directional oxidative ring expansion was used to prepare bis-enones such as (2R,6S,2'S)-6-methoxy-2-(6-methoxy-3-oxo-3,6-dihydro-2H-pyran-2-ylmethyl)-1-(toluene-4-sulfonyl)-1,6-dihydro-2H-pyridin-3-one from the

• (Scheme 2).[24][25][26][27][28][29][30][31][32] Two-directional[33] oxidative ring expansion of 1,3-difuryl 1,3-amino alcohol derivatives 4 would yield a densely functionalised bis-enone which would be ripe for further functionalisation. The term "two-directional synthesis" is usually used to describe the

• dihydroxylation reactions to the point that synthetically useful and complementary methods emerged; the most useful reactions were subsequently exploited in the two-directional synthesis of aza-C-linked disaccharide derivatives. For the syn allylic alcohols 15, 17 and 18, the dihydroxylation under Upjohn