Enantioselective synthesis of 11-substituted 2- or 3-methoxy-17-vinylgona-1,3,5(10)-trien-13-ols

The acylation of the (±)-spiro-γ-lactone 1 lithium enolate (3 equiv) by the O-TBDMS methyl (−)-(S)-lactate, the O-TBDMS methyl (+)-(S)-mandelate, or the diacetone-d-glucose carbonate (1 equiv each) occurs with a kinetic resolution. The (S,S)-enolate is the most reactive with the lactate and it is the (R,R)-enolate, which selectively reacts with the mandelate or the DAG carbonate. After alkylation of the resulting acyl lactones with 4- or 5-methoxy-1-iodobenzocyclobutene and heating, title compounds were obtained and, after deprotection, the structures of the optically pure new steroids were ascertained by single crystal X-ray analysis.     

The Crystal and Molecular Structure of 3-Oxo-17β-acetoxy-Δ4-14α-methyl-8α, 9β, 10α, 13α-estrene

The crystal and molecular structure of 3-oxo-17β-acetoxy-Δ⁴-14α-methyl-8α, 9β, 10α, 13α-estrene, C₂₁H₃₀O₃, has been determined by X-ray diffraction analysis. The crystals belong to the orthorhombic space group P2₁2₁2₁, with the cell dimensions a = 12.093 Å, b = 19.667 Å, c = 7.746 Å; Z = 4. Intensity data were collected at room temperature with an automatic four-circle diffractometer. The structure was solved by direct methods and the parameters were refined by least-squares analysis. All the hydrogen atoms were included in the refinement. The final R value was 0.038 for 1413 observed reflections. The conformation of ring A is intermediate between a half-chair and a 1, 2-diplanar form. The hydrogens at C(9) and C(10) are anti, the B/C ring junction is trans, and rings B and C adopt chair conformations. Ring D is cis fused and is halfway between C₂ and C_s forms.